Physicists Create Quantum Link Between Photons That Don't Exist At the Same Time

sciencehabit writes "Physicists have long known that quantum mechanics allows for a subtle connection between quantum particles called entanglement, in which measuring one particle can instantly set the otherwise uncertain condition, or 'state,' of another particle—even if it's light years away. Now, experimenters in Israel have shown that they can entangle two photons that don't even exist at the same time. Anton Zeilinger, a physicist at the University of Vienna, says that the experiment demonstrates just how slippery the concepts of quantum mechanics are. 'It's really neat because it shows more or less that quantum events are outside our everyday notions of space and time.'"

Comments

Wait for the retraction

[ssufficool]

Faster than light speed is possible... but wait, we need "Exotic" materials that don't exists. We entangled particles to communicate across time and space, no wait. we measured it wrong. I give it a week before other scientists call bullshit.

Re:Wait for the retraction

[Anonymous Coward]

You really have no idea what you're talking about do you?

Re:Wait for the retraction

[socceroos]

The problem with quantum mechanics is that we suck at measurement. This really does put a spanner in the general workings of testing scientific theory.

Re:Wait for the retraction

[Z00L00K]

If it is actually possible to utilize the entanglement there are a number of commercial possibilities as well as governmental. Communication that is hard to spy on, faster communication across the globe, instant communication with remote operated vehicles on other planets.

But we don't know until we have freed Schrödingers Cat - or has it actually teleported itself to another plane of existence?

Re:Wait for the retraction

[kermidge]

Let me guess, tl;dr?

Re:Wait for the retraction

[Anonymous Coward]

Faster than light speed is possible

We already knew that. Whatever gravity is it already shows us this. The Earth is approx. 8 light-minutes from the Sun. The Sun is of course moving. If the Earth revolved around where the Sun was 8 minutes ago, it would long ago have drifted out of the solar system. Gravity operates faster than light.

Re:Wait for the retraction

[Anonymous Coward]

I think you'll find gravity wibbles a bit, sort of like rubber the motion of the sun flows down that rubber bit at the speed of light and affects the position of our planet 8 minutes after the sun has since moved but since it's a more dynamic relationship due to the effect of gravity, we continue to follow the sun.

Re:Wait for the retraction

[mark-t]

The same forces that are moving the sun through space are also acting on the earth itself. So, no.

Re:Wait for the retraction

[MaxToTheMax]

Possibly using excessively hostile phrasing, but this poster is right-- I'd say the chances of the results not being reproducible are high.

Re: Wait for the retraction

[Anonymous Coward]

Ooooh. So much edginess.

Re: Wait for the retraction

[dmbasso]

Ooooh, So much ooohs.
Somehow, suddenly I want to play Monkey Island again.

Re:Wait for the retraction

[quax]

We already knew that.

Whatever "we" you mean count me out.

According to GR gravity is facilitated via a retarded potential, and of course GR survived so far every conceivable test and has been shown to make correct predictions were Newtonian gravity failed.

So no, gravity does not operate faster than light.

Re:Wait for the retraction

[Gogogoch]

Rubbish. Gravity is not FTL, and your argument is BS.

Re:Wait for the retraction

[Gogogoch]

I doubt this is BS, sounds authentic to me. Quantum mechanics is weird. As for the "outside ... space and time", note that the missing words from TFA are "outside everyday notions of space and time". In other words, outside our common sense.

Re:Wait for the retraction

[Anonymous Coward]

The Earth does revolve around where the sun was 8 minutes ago.

Re:Wait for the retraction

[Pseudonym]

Yeah, this. What the AC may be confused about is that faster than light travel is (as far as we know) not possible in space, but the distance between two points can increase faster than light could travel because there's nothing stopping space itself from expanding that fast.

Re:Wait for the retraction

[dgatwood]

I'm pretty sure we already know the answer. The cat is dead. Curiosity killed it.

Re:Wait for the retraction

[Anonymous Coward]

you can't transmit information faster than light. also states so in the article. not that i understand why.. spy-proof communication is probably feasible, though.

Re:Wait for the retraction

[Anonymous Coward]

The distance between two objects does not increase faster than light relative to each other. You need to study the Lorenz transformation equations.

https://en.wikipedia.org/wiki/Lorentz_transformation

If one object far away is moving .9 times the speed of light away from you and another object, in the opposite direction, is moving .9 times the speed of light away from you then those two objects, relative to each other, are not moving faster than the speed of light away from each other. They are moving like .99 (or whatever, you have to do the calculations) times the speed of light relative to each other.

Re:Wait for the retraction

[maxwell demon]

Lorentz transformations only cover special relativity. In general relativity, you can indeed have the distance between two points grow faster than light. Of course not if the points are at the same place.

Re:Wait for the retraction

[shentino]

Except that the Earth's motion relative to the galactic core already roughly matches that of the Sun (relative to the galactic core).

Lern2frameofreference.

Re:Wait for the retraction

[Pseudonym]

Precisely.

OK, not precisely. Two points at the same place at the same time is one point, not two points. But I knew what you meant.

Re:Wait for the retraction

[Anonymous Coward]

Or it must have been there in the future?

Re:Wait for the retraction

[Trax3001BBS]

I give it a week before other scientists call bullshit.

I see it as something they wanted to prove and did to themselves and anybody else who wants to believe their results or just their word.

Entanglement is related to particles from the same event. 1&2 are entangled as are 3&4.
1&4 were considered entangled by their use of "projective measurement" on 2&3

"projective measurement" = Although quantum mechanics has held up to rigorous and thorough experimental testing,
many of these experiments are open to different interpretations
http://en.wikipedia.org/wiki/Interpretation_of_quantum_mechanics
linked from http://en.wikipedia.org/wiki/POVM defining "projective measurement" (first paragraph).

So they have their interpretation, I have mine (didn't happen), and we're all happy.

About me: A two years of chemistry ex-student who does a lot of reading on quantum physics. Yet nobody to talk on the subject, so more reading.
Not trying to solicit anybody just saying nobody I know, knows much on the subject to bounce thoughts off of.

Re: Wait for the retraction

[dmbasso]

s/much/many/g

Just waking up and writing in non-native language requires coffee.

Re:Wait for the retraction

[Cenan]

Lorentz transformation and Einstein's theories govern motion in space. Space itself can expand at much greater velocities than c. The Observable Universe is something like ~80 billion LY across (today), but the objects furthest from us are ~14 billion LY away (when they emitted the light). If space could not expand faster than c, it would only be ~14 billion LY across today. Look up inflation if you're genuinely interested.

Re:Wait for the retraction

[Z00L00K]

Everything is theoretically impossible, until it is done.
Robert A. Heinlein

Re:Wait for the retraction

[Anonymous Coward]

Even in the simplest model, this just gives an Earth consistently rotating around a 'phantom sun' (8min)*(speed_of_sun) behind the actual sun, with no departure from the solar system.

A more thorough model, however, presumably allows one to use a reference frame in which the sun is stationary (or, for that matter, in which the Earth is stationary and the rest of the universe including the Sun revolves around it?) without abnormality.

Re:Wait for the retraction

[Trogre]

So what's stopping space itself from contracting that fast, ie reducing the distance between two points?

Re:Wait for the retraction

[jamesh]

Rubbish. Gravity is not FTL, and your argument is BS.

I suspect a whoosh might be in order here... "The Sun is of course moving" should have been a dead giveaway.

Re:Wait for the retraction

[gagol]

Number stations and one time pads already fill the need for "spy proof" communication.

Re:Wait for the retraction

[Cenan]

Dark energy - a term coined to hide the fact that "we don't know". Dark energy seems to be accelerating the expansion after a period of deceleration, this is baffling but fits observational results. The theory is that gravity used to slow the expansion down, but apparently we passed a cut-off point where space has become stretched enough so that gravity is too weak - another force is taking over and stretching space again. A force with no obvious cause, not to us at least.

Re:Wait for the retraction

[michelcolman]

Entanglement can be used to exchange keys for secret communication. It allows two parties to create a shared key without anyone being able to intercept it. In principle, this key can be as long as the message itself and perfectly random, so a simple 'xor' operation is all it takes to make the message completely undecryptable. In more detail:

Alice wants to send a secret message to Bob.
They (or anybody else, really) create a bunch of entangled photons, half going to Alice and the entangled counterparts going to Bob. This all happens at normal speeds (not faster than light), but can be prepared in advance.
If anyone tries to eavesdrop during transmission of the entangled photons, Alice and Bob are able to detect the fact that the photons are no longer in a superimposed state and start over with a new bunch.
Now Alice and Bob measure the photons. They have no control over the outcome of the measurements, which will be completely random, but they do know that they will both get the same result (or rather, exactly the opposite result). This becomes their cryptographic key.
Now Alice encrypts her message with this key and sends it to Bob using traditional communication channels, for example a carrier pidgeon.
Bob uses his identical key to decrypt the message.

The only faster-than-light part of the story is that the entangled photons "chose" their state at the time of the measurement. Before the measurement, they were in a superimposed state. This means the information for the key didn't even exist yet in any way and can therefore never be intercepted by anyone. It only came into existence at the time the photons were measured, simultaneously for Alice and Bob. (Take the word "simultaneously" with a grain of salt, because as the article shows, they can even be separated in time). And the encrypted message without the key is just a series of random bits.

Re:Wait for the retraction

[flayzernax]

Because the information needed to test the entanglement requires conventional transmission. There is no way to prove the postulated quantum teleportation of the information. Or both particles need to be created under lab like perfect conditions and moved apart. Which won't happen faster then relativistic speeds. Therefore we observe no breaking of causality.

I think a few people have claimed causality breaking on occasion but the general scientific consensus is that isn't what is happening. There was a much more interesting experiment out of Los Alamos which I do not remember where they tested causality in time in a fairly robust way that leads me to believe it may be possible. But I cannot remember and cite it =/. It was also backed by the Chinese in a later experiment. But they have been getting a lot of raft for bad science and research lately.

Re:Wait for the retraction

[flayzernax]

I think in the most simple terms the experiment went like this:

Particle A set was measured having a statistically consistent result, particle set B was not measured.
Particle set A was measured again.
Particle set B was measured for the first time and had a different result then particle set A.

They postulated that performing the measurement #2 is what caused A's measurement to be consistent.

The interesting bit of the experiment was how they were measuring particles. However I can't explain it.

In other words IANAPhysiscist and you should take what I am saying here with a grain of lots of error inducing salt.

Re:Wait for the retraction

[Anonymous Coward]

Yikes, it's scary that you think you're right.

Re:Wait for the retraction

[michelcolman]

Space itself can expand at much greater velocities than c.

To explain this in a little more depth, what we call "space" is really just tied to an arbitrary choice of space-time coordinates. If we choose a different reference frame, distances and times will be different. Just to give a silly example, if I define a meter to be the width of an atom, or if I define a second to be the time required for the earth to go around the sun a thousand times, I can easily travel faster than c. So how does this apply to cosmology and general relativity?

Depending on the coordinate system you choose, the universe can really look radically different, even to the point of no longer being infinite. I will give two possible views, both equally valid even thought the first may appear strange. (So read the rest as well before labeling it as rubbish).

You can apply a classic "special(ly?) relativistic" coordinate system to the universe, with us at the center. The speed of light is the same everywhere, relative to us, just like Einstein said in the beginning. Things that are far away from us are moving away at high speed (but less than the speed of light) and are therefore aging more slowly. This means that some far away galaxy isn't just younger (defined as the amount of local evolution after the big bang) because we had to wait for its light to get to our telescope, it actually is younger "right now" even if we take the traveling time of light into account. Local clocks are really advancing more slowly. The effect increases with increasing distance, and at a distance of c times the age of the universe, the big bang is happening as we speak. Right now. This also means that the universe is finite (assuming nothing existed before the big bang, which is a big assumption). Not that it matters much, because we could never reach this "edge" anyway. It is retreating at the speed of light.

This model is quite interesting but a bit cumbersome for cosmology, so most people prefer to use the "cosmological model". They simply adjust the coordinates of time and space so that the whole universe is the same age and looks roughly the same everywhere, "right now". See, we just changed the definition of "now" and chose a coherently matching set of space coordinates so everything looks rougly the same size, that's all we did. In General Relativity, we are completely free to do so, you can pick pretty much any coordinate system you like. Things can move from the future into the past and back again as we change our variables, without impacting causality (which is all that matters).

Using the cosmological model, the universe is now truly infinite, the big bang is in the distant past everywhere and all the clocks are running at the same speed (as long as they are stationary relative to "space", i.e. moving away from us at the same speed as the average local galaxy). Now, however, the assumptions of special relativity no longer hold. In particular, the speed of light is no longer the same everywhere. Light speed is still the same everywhere locally, relative to "space" (the speed of the average galaxy in that area), but you have to take the properties of our peculiar coordinate system ("expanding space") into account. If at some distance, "space" and the objects in it are expanding away from us faster than the speed of light, the light from those galaxies will never reach us since it will actually be retreating as if it were running towards us on a conveyor belt moving the other way at a higher speed. The conveyor belt isn't "real", it's just an artifact of our choice of coordinates which does not comply with special relativity.

In the first model, those distant galaxies simply never come into existence since the local "space" is asymptotically stuck at a time shortly after the big bang. Things over there are moving away from us at increasing velocity approaching c, and time (rate of aging of that part of the universe) is grinding to a halt.

But do those places exist or not?

Re:Wait for the retraction

[Anonymous Coward]

Why is it you hardcore science types are so terrified that the speed of light may not actually be a hard constraint? Doesn't it excite you to consider the possibility that, once again, we just might be wrong about something?

Science looks more and more like a religion every day.

Re: Wait for the retraction

[AikonMGB]

He knows.. which is why he corrected himself...

Re:Wait for the retraction

[Bengie]

I was just watching a PBS Nova on quantum stuff and one of the more recent tests involved entangling two quantum photons, sending one of those photons several miles away, then entangling the local-photon with another non-quantum photon, causing the local-photon to take on the opposite state of the known-photon, causing the remote-photon to take on yet that photons opposite state, effectively re-creating the exact state of the known-photon, instantly, but destroying the known state of the local known-photon.

This caused that state of a known photon to be transferred faster than light, but did destroy the known state of the original local known-photon in the process. The Doctor said based on this finding, we can transfer information faster than light, but not without destroying the original.

This experiment has been repeated by the same team several times and seems to be very hard to pull off, but is getting setup to be reproduced by others.

That is unless a leading Doctor in quantum physics on the PBS Nova channel is not a reliable source and assuming it's reproducible by other teams.

Re:Wait for the retraction

[Anonymous Coward]

Interesting detail: If dark energy really exists and is responsible for making the universe expand, then it would be a kind of "anti-gravity"?

Re:Wait for the retraction

[Anonymous Coward]

I know about inflation and I was trying to explain to you that no two objects, relative to each other, move away from each other faster than C. But you're still not getting it I suppose.

Re:Wait for the retraction

[Bengie]

Gravity is less than or equal to light. Earth will continue to orbit where the Sun was for 8 minutes. About the exact same time that the light disappears, we will suddenly start moving in a strait line again.

Re:Wait for the retraction

[Bengie]

Space near a blackhole can be distorted in a way that causes the space to move faster than c, keeping light from escaping. This can cause light to move backwards relative to an object. Relative to the space that the photon is in, it is still moving forward at c.

Re:Wait for the retraction

[michelcolman]

Of course I disregarded gravity in my post. Black holes are a whole different ball game. But there too, you can use different coordinate systems to get different interpretations of the events, always yielding the same tangible results.

For example, you could easily argue that, at this moment, no black holes exist. Just before the black hole really becomes a black hole, local time will have slowed down so dramatically that it never actually becomes a black hole. It's forever stuck at the stage right before becoming a black hole. But change to a different reference system and there you go, they exist after all. Just change your definition of "now". In the second system, light inside the black hole may actually be retreating away from us even though it was aimed in our direction while in the first system, it is simply never emitted. I bet people have come up with reference frames that have time going backward inside black holes too. Or going imaginary (the complex number kind of imaginary). But no matter how you define your seconds and meters, you'll always get the same results if you apply General Relativity.

Re:Wait for the retraction

[K. S. Kyosuke]

The Earth is approx. 8 light-minutes from the Sun. The Sun is of course moving. If the Earth revolved around where the Sun was 8 minutes ago, it would long ago have drifted out of the solar system.

Wow, you suck at basic Newtonian relativity. How's that even possible?

Re:Wait for the retraction

[K. S. Kyosuke]

I doubt this is BS, sounds authentic to me. Quantum mechanics is weird.

Well, after I had read that the double slit experiment works for such large things as buckyballs (C60), I vowed not to let myself get surprised by QM anymore. So far, I haven't faltered. :-)

Re:Wait for the retraction

[dbrueck]

Wish I had some mod points right now - thanks for taking the time to explain this!

Re:Wait for the retraction

[Anonymous Coward]

Not bad.

If you shot one object at .6 C in one direction relative to you and another object at .6 C in the opposite direction (relative to you) then when you add the two velocities you get 1.2 C. But if you were on one of the objects looking at the other you will not see it moving away from you at 1.2 C, you would see it moving away from you at less than C, maybe .8 C (you would have to do the math) even though both objects are in close proximity to each other.

Same principle here. No two objects in space move away from each other, relative to each other, faster than C.

Re:Wait for the retraction

[khallow]

It's worth noting here that neither point need actually move (or they could be moving towards each other a significant portion of the speed of light). It's the space in between which is growing longer.

Re:Wait for the retraction

[Anonymous Coward]

and the reverse can also be said. If you were standing ten meters away from someone else and you shot an object at .6 C directly at them and, at the same time, they shot an object at .6 C directly at your object so that both objects will collide head on you would think that the objects are closing in on each other at 1.2 C. But if you were an observer on one object looking at the other you would not see it approaching you at 1.2 C, you would see it approaching you at less than C.

Everyone thinks that because one galaxy is moving away from me, relative to me, at .9 C in one direction and another is moving away from me at .9 C in the opposite direction (relative to me) then they are moving away from each other at faster than C. Not relative to each other though.

Re:Wait for the retraction

[Anonymous Coward]

This is the basis for a warp drive.
You contract the space infront of the ship, while expanding the space behind. The ship itself remains inside a "warp bubble" while you move space around outside the bubble.

To test this they're trying to create a bubble in the lab and shine one of a synced laser pair through the bubble region. If the lasers are out of sync, then they've managed to create a bubble and distort space.

http://www.popsci.com/technology/article/2012-03/pro-tip-flying-faster-speed-light-could-have-devastating-consequences
http://www.popsci.com/technology/article/2013-03/warp-factor?single-page-view=true

Re:Wait for the retraction

[Anonymous Coward]

If someone comes up with a repeatable experiment that shows that FTL is doable then it would be accepted as it got peer reviewed & repeated by virtually every scientist.

If someone comes up with a repeatable experiment that shows that god is a load of bollocks then it would ignored or brushed under the carpet with "well God made it that way".

So, no nothing like religion really. One can (and has) changed as new facts were discovered, the other can change as society changes but not easily.

Re:Wait for the retraction

[Paradigma11]

but if you are able to detect if photons are superimposed then you are able to transmit information faster than light violating causality. Or do you mean detecting by trying to communicate with differing keys?

Re:Wait for the retraction

[ceoyoyo]

We're very good at measurement. Quantum mechanics only says that you can't measure everything exactly at the same time, you have to make lots of measurements and use statistics. Which is what we do anyway.

Re:Wait for the retraction

[ceoyoyo]

You can only detect the superimposition given information transmitted in a normal way, so you can never detect it faster than a normal signal takes to travel to you.

Re:Wait for the retraction

[ceoyoyo]

Just to give a silly example, if I define a meter to be the width of an atom, or if I define a second to be the time required for the earth to go around the sun a thousand times, I can easily travel faster than c. So how does this apply to cosmology and general relativity?

That's a pretty silly example, seeing as how it's wrong. If you choose to define a "metre" as the "width of an atom" then you will still not be able to win a race with a beam of light any more than I could run faster than a Ferrari. You might be able to travel more metres per second, but so would the light.

Re:Wait for the retraction

[ceoyoyo]

Do you not believe that the Sun is moving?

Re:Wait for the retraction

[Gripp]

http://gizmodo.com/government-lab-admits-to-using-quantum-internet-for-two-493293340

Re:Wait for the retraction

[Anonymous Coward]

By saying quantum mechanics is simply because we suck at measurement, you are either demonstrating you are horribly uninformed about quantum mechanics (maybe too many pop-sci analogies), or are really bad at conveying your actual point. There are a whole host of experiments and examples that would be covered in any introductory course or book on quantum mechanics showing why it isn't just a matter of bad measurements.

Re:Wait for the retraction

[Anonymous Coward]

That explanation skips a step. When you transfer the state from the photon you want to copy to the distant photon, it doesn't instantly create an exact copy. It creates a copy that has been affected by one of a small number of random transformations (e.g. if measuring up vs. down, you have a 50-50 chance that the new copy was a copy that was flipped). A measurement made on the destroyed copy allows you to tell which transformation was applied to the new copy. In order to make the new copy an actual, exact copy, you need to know which transformation was made, so that you can undo it (e.g., if it was flipped, you have to flip it back, if it wasn't flipped, you need to not flip it). The only way to know that is to wait for the sender to tell you by classical means after they made their measurement of the destroyed copy. Otherwise, you get a random result instead of a copy at the destination.

In other words, it is like the process of teleporting doesn't make a copy, it makes a copy with a randomly chosen one time pad, and you need to get that one time pad from the sender, after they have sent the messed up copy. Without a one time pad, the received message would be completely randomly scrambled.

Re:Wait for the retraction

[Anonymous Coward]

By two points at the same place, it means two points close together, not necessarily on top of each other (i.e. one point). In general relativity, if you zoom in enough on any spot in space, it will look flat and like just special relativity. This is usually described by saying that in GR, it is locally flat. The only question is to define "close enough," which depends on the situation.

Re:Wait for the retraction

[Anonymous Coward]

The thing about interpretations of quantum mechanics, is in the end, they don't make any predictive difference. They might make things fit together better in your head, or act as a muse when looking at the math, but in some sense they don't change the experiment. It is just a layer of abstraction on top of the math that works. While, because of the muse part, it is important to know of these interpretations when doing quantum mechanics work, it is easy to spend way too much time thinking or working on the interpretation part without any actual science gain, and it becomes a slightly disjoint philosophy instead of science (not that it is a bad thing, just may be a different priority).

Re:Wait for the retraction

[Anonymous Coward]

Doesn't it excite you to consider the possibility that, once again, we just might be wrong about something?

Yes, constantly, even though the field of physics I am in is not quantum mechanics.

Why is it you hardcore science types are so terrified that the speed of light may not actually be a hard constraint?

I don't know about "science types" but for scientists, it is not being terrified that the speed of light is not a hard constant, but being terrified of being hasty and making a mistake.

The problem I see with some people asking questions like that, is they ask why should scientists doubt a new result, as if to imply it is a simple choice between two equal options: trust the new result or not trust the new result. What it actually comes down to is, do you want to doubt the new result, or doubt the huge multitude of results that came before it? It is not that the multitude of results that came before can't be wrong, but they have had a lot of cumulative scrutiny while new results don't. It doesn't take long working in such fields to see that it is really easy to make small mistakes that invalidate new results, and lot of effort can and has been wasted taking things too far, too fast.

If there are ways to travel faster than light, they will still be there in a couple years after people examine the details of experiments that suggest so. If we are too quick to disregard past results though, it will take a lot more than a couple years to make solid progress in any direction.

Re:Wait for the retraction

[Anonymous Coward]

I'd just like to take the time to thank you for that. Far too many people (especially here) who consider themselves well informed will simply state the accepted fact without any explanation as to why it is expected. Over the years I have seen many slashdotters modded down for suggesting that gravity might be faster than light but very few of their critics have actually cited the correct argument.

When you think about it, someone who is given the argument about the moving sun on the one hand, and a "na-na can't hear you, you quack" on the other, must (if he is completely uninformed and unbiased) rationally conclude the former. I suspect that many of those who shout them down don't actually know the reason, but that is just a gut feel. Thank you once again, and keep it up.

Re: Wait for the retraction

[dragon-file]

Edgy... You keep using that word. I dont think it means what you think it means.

Re:Wait for the retraction

[Anonymous Coward]

When you think about it, someone who is given the argument about the moving sun on the one hand, and a "na-na can't hear you, you quack" on the other, must (if he is completely uninformed and unbiased) rationally conclude the former.

No, only a lazy person must conclude the former, or latter. A rational and motivated person would see there might be something here and look at an actual resource on the subject instead of basing their decision on two random forum posts.

It is unfortunate that some slashdotters counter arguments without any details. Although in cases I'm familiar with, it seems understandable though, considering the details they left out on some topics are included in nearly every introductory thing written about the topic and including on Wikipedia. It is kind of easy at times to let yourself get jaded when people try to argue something while ignoring the basics and demonstrating they took virtually no effort to learn things themselves and expect others to spoon feed them (and half the time fling the spoon away...). So it is unfortunate when those that are interested and could learn a lot on a new topic instead just see and argument that amounts to "Yes" vs "No." But I would hope that people with any sense would be able to identify when something might have a decent chance of having been written about at length already and not depend on slashdotters to rewrite that or link that for them.

Re:Wait for the retraction

[painandgreed]

Dark energy - a term coined to hide the fact that "we don't know".

It's not a term to hide the fact that "we don't know", it's a term to punctuate that "we don't know". If we were really trying to hide stuff, we'd define it as stuff we already know about rather that come up with a new term (like the MOND guys are doing with dark matter).

Re:Wait for the retraction

[Anonymous Coward]

Not in my preferred frame.

Re:Wait for the retraction

[Anonymous Coward]

Why is it you hardcore science types are so terrified that the speed of light may not actually be a hard constraint

Its far from a hard constraint. All equations work just fine for things going faster than light if you are willing to apply additional constraints on cause and effect.

There is a small problem when something with mass going at exactly "C" requires infinite energy.

And of course all of this is frame specific. If you had your own rocket ship you can go at any speed you want as fast as your thusters can carry you. If your rockets were filled with liquid schwarts you could get to Alpha Centuri within 4 minutes according to your watch rather than the slow 4 years it takes light to travel there. The only problem is people watching your journy would think you actually took slightly more than 4 years.. Who cares what *other* people think anyway?

Please note these concepts apply only for things *propagating* thru space. Quantum correlations do not "propagate" and hence are not subject to our silly notions of distance. Creating wormholes to provide shorter trip thru less space is also not forbidden.

Doesn't it excite you to consider the possibility that, once again, we just might be wrong about something?
Science looks more and more like a religion every day.

Such consideration requires supporting evidence. There are people looking for tachyons - thus far noone have found any.

There are no shortage of people looking for violations of conservation laws in fact such endeavours are directly responsible fordizzying array of advancements.

We all have limited time and resources. To get anything done it is imperative we apply some filters to what we are willing to spend our time and energy on. There is plenty of human dogma to go around. The core difference at the end of the day evidence eventually trumps dogma.

Yelling religion because your pet theory encrusted in lay person (science speak for dumbass n00b) ignorance is summarily ignored is no different than a child yelling for attention. It is a reflection of *your* failing nobody elses.

Re:Wait for the retraction

[michelcolman]

Actually, they would have to compare some subset of the key over a classical channel, to detect eavesdropping and then use the remainder of the key for the actual secret communication.

Re:Wait for the retraction

[michelcolman]

Yes, light speed would be orders of magnitude greater than c with those silly definitions. Which is exactly the point: both light speed and the speed of local objects at different places in the universe can be different depending on which reference system you use, and this explains why things can go "faster than light" in some models, and light speed isn't always 'c'.

To make the comparison a bit more accurate: suppose I defined a non-cartesian reference system where the size of a metre depends on the distance to earth. Here on earth, it is the width of an atom but on Mars it's the length of our traditional metre. I can then go "faster" on earth than a ray of light on Mars since the ray on Mars is only doing 300000000 metres per second and I am doing more "metres" per second here. Of course that's still a silly example, but it's quite similar to what's happening in the cosmological model.

A reference frame that obeys special relativity will have the same light speed everywhere, and all objects will travel slower than c, but in the cosmological model light speed will have "the expansion of space" superimposed on it and objects travel away from us at speeds higher than c (but slower than local rays of light in the same direction). It's all just because of the coordinates used. Normally, objects moving away from us at high speed will be contracted in the direction of motion but the cosmological model uses contracted metres that make everything the same size again. And the scale keeps changing as the universe expands, artificially "moving" objects to ever greater distances. And clocks are artificially sped up. All of this throws Special Relativity out the window.

No matter which reference frame you use, you will never be able to outrace a beam of light at the same location as you. But you may be able to go "faster" than a beam of light that is many billions of light years away, since the "faster" just depends on arbitrary measurements without a direct objective relationship. In any case you can't actually physically pass a beam of light in the same direction as you.

Re:Wait for the retraction

[Aerokii]

"Things are only impossible until they're not." -Captain Jean Luc Picard

Re:Wait for the retraction

[michelcolman]

No two objects in space move away from each other, relative to each other, faster than C.

Just to make a tiny correction: relative to each other, as measured by one of them. If we measure them, using our reference frame, we will definitely see them moving away from each other at a relative speed of 1.2 c. Each second, the distance between them will have increased by 1.2 light seconds. But if you are on board of one of the objects, you will have a different clock and different distance scales. You will then measure 0.88 c.

Re:Wait for the retraction

[michelcolman]

Everyone thinks that because one galaxy is moving away from me, relative to me, at .9 C in one direction and another is moving away from me at .9 C in the opposite direction (relative to me) then they are moving away from each other at faster than C. Not relative to each other though.

Well, if they are moving away from us at that speed due to the expansion of the universe, and everybody uses the cosmological model, then even the aliens in one of the galaxies will agree that the other galaxy is moving away from them at 1.8 c. Because that's due to "the expansion of space" (or in other words, the peculiarities of the cosmological model). If everybody uses models based on special relativity, the aliens will only measure the other galaxy at 0.99 c.

Re:Wait for the retraction

[Anonymous Coward]

This might be going a bit too far, as you can't arbitrarily pick a coordinate system, while using the same laws, etc. However, the coordinates used in general relativity are a rather specific set of coordinates (although some variations get used, other relations have to be re-derived). The coordinate system you describe with definition of length depending on distance from Earth, with some considerable effort, can be used, but you would need to re-derive how various laws in more normal coordinate systems, and you would recover a speed limit that amounts to just c in normal coordinates but now with some more complicated expression in the different coordinates.

But you may be able to go "faster" than a beam of light that is many billions of light years away, since the "faster" just depends on arbitrary measurements without a direct objective relationship.

The definitions of coordinates used in cosmology are far from arbitrary and have objectivity. There is specific meanings behind what distance and speeds mean, although a lot of that gets dropped from actual papers when summed up in more accessible material.

You are right that you won't pass a beam of light in the same direction, because in GR it will always locally look like special relativity. But it is possible to have a beam of light shined directly at you, and have it never be able to reach you in finite time, while at the same time have its distance always increasing from the source.

Re:Wait for the retraction

[ceoyoyo]

You seem to be confusing c, the speed of light in a vacuum, with 3.00 x 10^8, the number describing the speed of light in a vacuum using units defined to particular international standards. The speed of light doesn't change when you measure it in m/s, km/h or ft/day. You can of course define any units you want, with any silly inconsistencies you want, and can make up all kinds of silly results based on those. Real measurements aren't arbitrary, although they can be made to seem so when you choose an inconsistent measurement system. We try not to do that.

Re:Wait for the retraction

[michelcolman]

The definitions of coordinates used in cosmology are far from arbitrary and have objectivity. There is specific meanings behind what distance and speeds mean, although a lot of that gets dropped from actual papers when summed up in more accessible material.

Well, with "arbitrary" I didn't mean to say there were no good reasons for using the cosmological model, quite the contrary. Obviously it's easier to use a reference frame in which the infinite universe is homogenous and the same age everywhere. I'm just saying that it's one of several possible choices of coordinate systems, and other choices would yield different times, distances and speeds. The whole idea of "space expanding faster than light" is in a way caused entirely by this particular choice of coordinates. The special-relativistic model (which pretty much nobody uses, for good reasons) does obey the speed limit but has the disadvantage of not being homogenous and treating our milky way as a special location at the center of a finite universe (like I described in my earlier, great-grandparent post).

I do prefer the cosmological model, but I think it's useful to point out exactly what it means, and where the contradiction with Special Relativity is coming from. Too many popular publications just say "space itself is expanding faster than light, and that explains it" while "space itself" doesn't really mean anything. They make it seem like space is some kind of expanding aether, which of course it isn't. Stuff in space happens to be flying apart, and we just chose a system of coordinates to make the description of the stuff easier. This happens to have the side-effect of creating the notion of an expanding "space" on top of which c has to be superimposed, but that's just a mathematical artefact caused by the choice of space-time coordinates.

You are right that you won't pass a beam of light in the same direction, because in GR it will always locally look like special relativity. But it is possible to have a beam of light shined directly at you, and have it never be able to reach you in finite time, while at the same time have its distance always increasing from the source.

Exactly, and I gave that example in my earlier great-grandparent post. In the cosmological model, the light from distant galaxies will never reach us because space is expanding too rapidly. In the special-relativistic model, that galaxy will never exist in our reference frame since its ancestral matter is moving away from us at a speed so close to c (and increasing towards it) that the passage of time is asymptotically grinding to a halt. Both views are consistent with the actual fact that we will never see that galaxy.

Re:Wait for the retraction

[michelcolman]

Well, I'm not going to argue about the exact definition of c, but I certainly meant the fixed mathematical value. The silly example just tried to show how it is possible for things to go faster than c without causing any problems with relativity. If you choose a coordinate system that is not consistent with the definitions used in Special Relativity, then yes, you will find speeds greater than 3 x 10^8 m/s. This can be very useful, as is the case with the cosmological model (which, unlike my silly example, does preserve "local" speed of light but not global speed of light throughout the universe).

My silly example served no purpose other than to make the point that speeds are just something measured in some coordinate system and therefore the choice of coordinates can change the values. The notion of a galaxy moving away from us at some specific speed only has meaning if we also describe the reference system being used.

If we are using the cosmological model, it is perfectly normal for galaxies to be flying away from us at many times c. With a different set of coordinates, obeying the definitions of Special Relativity, we will only find speeds lower than c but the universe will look distorted because of lorentz contraction and time dilation. Which is why pretty much anyone uses the cosmological model and explains the resulting high speeds as "space itself expanding".

Re:Wait for the retraction

[jamesh]

Do you not believe that the Sun is moving?

Not relative to the Earth's frame of reference it isn't, which is all that matters for this calculation.

Re:Wait for the retraction

[Anonymous Coward]

If we are using the cosmological model, it is perfectly normal for galaxies to be flying away from us at many times c. With a different set of coordinates, obeying the definitions of Special Relativity, we will only find speeds lower than c but the universe will look distorted because of lorentz contraction and time dilation. Which is why pretty much anyone uses the cosmological model and explains the resulting high speeds as "space itself expanding".

Either you are grossly oversimplifying things here or are missing something. Special relativity is not applicable on the global scale here. Assuming the cosmological models are anywhere vaguely close to accurate, a Minkowski spacetime could not be used, just as such a coordinate system would fail horribly near a gravitational body if examined closely enough (or for a dense enough body). I'm not sure what you mean by the universe would look distorted under such a coordinate system, as there is very little flexibility in the coordinate systems within special relativity and they don't fit the situation.

With relativity, special or general, the speed of light, as represented by c, would the same in any coordinate system compatible with those theories. The actual number is irrelevant, and in fact, most GR theorists set c=1 to save them from having to write it so many times in equations. But that doesn't mean a coordinate system that allows for movements above 1 m/s is faster than light.

Re:Wait for the retraction

[sFurbo]

I think the best description of why is "General relativity - causality - Faster than light information transmition: Pick two". Or, more user friendly, in general relativity, FTL communiation is equivalent to the reversal of causility, with event B affecting event A, even though B takes place after A.

Now, we have pretty good evidence for general relativity, and causality also tends to hold up, so the general assumption is that FTL communication cannot happen.

Re:Wait for the retraction

[Rich0]

Yeah, this. What the AC may be confused about is that faster than light travel is (as far as we know) not possible in space, but the distance between two points can increase faster than light could travel because there's nothing stopping space itself from expanding that fast.

That's relativity, but the nice thing about this is that you can't actually observe it happening. If you put two golf balls in a room and then expanded the space between them so that they move a light year apart in a second, you'd never see either golf ball moving faster than the speed of light away from you, whether you are viewing from the perspective of either ball, or an observer in the room. You'd just see them move apart at a speed very close to the speed of light.

Objects further away than the cosmic horizon are in theory moving away from us faster than the speed of light. However, if we look at them all we see is a background of objects close to the horizon that are so red-shifted that they're barely detectable at all moving away at almost the speed of light. We can't see beyond the horizon (hence the name), and we can only see the horizon itself as a wash of particles coming from every direction (otherwise known as the cosmic microwave background).

Re:Wait for the retraction

[bingoUV]

Since the Earth is moving in Sun's frame of reference, Sun is definitely moving in the Earth's frame of reference.

Sun is not moving in its own frame of reference, but nothing really is (if you forget the moment).

Re:Wait for the retraction

[michelcolman]

I did disregard gravity since the density of the universe is pretty low on a large scale, so maybe there are some corrections to be made to take the (small) curvature of the universe due to gravity into account, but I think most of my explanation is still valid. If you can just imagine a universe without (much) gravity, I don't think there's anything wrong with the models I described. I will just give them again with a bit more detail:

The first reference system I proposed is an extremely simple one (but with complicated consequences) constructed along the lines of special relativity:

1. Pick some "stationary" point in our vicinity as the origin (of course not the earth or the sun, since they are revolving around the center of our galaxy, but some point in our local cluster of galaxies should do fine).
2. Using a set of standard "measuring rods" (just like Einstein used in his popular description of relativity), which are placed stationary to the origin of the reference frame, construct three perpendicular axes to assign space coordinates.
3. Place a clock at the origin which sends out a signal every second. Clocks are also placed at various other places in the universe and synchronised by listening to the origin clock and applying a correction of distance divided by light speed. A clock located one light second away, for example, would add one second to the received time to indicate current time in our reference frame. All these clocks are stationary in our reference frame, they are not moving with the expansion of the universe.

In this reference system, distant galaxies are flying away from us at high speed and are therefore subject to lorentz contraction and time dilation. They will appear shrunk in the direction of motion, and will age more slowly. They are also closer together because the space between them is lorentz-contracted as well. Obviously, an alien civilisation in those galaxies would consider themselves to be the center, and would say we are aging more slowly than them, but that's just the classic twin paradox and no contradiction. We are free to use our own reference system.

Anyway, using this reference frame, objects at large distances are younger because they have been aging more slowly ever since the big bang. At some distance away from us, objects are traveling at speeds close to c and they are so young that the big bang has only just happened for them. A little bit further, at c times the age of the universe, there's a singularity where the big bang is happening now.

Of course I realise that this is a strange way of looking at the universe, but it obeys the principles of special relativity (disregarding gravity) and therefore has the property that nothing exceeds the speed of light relative to the origin.

The cosmological model, which is a lot more practical to use, is constructed in a different way. Clocks at any point in the universe are set so they indicate the amount of time passed since the big bang as experienced by a local observer that is moving with the expansion of the universe, and distances are measured so that local light speed, relative to a local observer moving with the expansion (i.e. relative to "expanding space"), is c. Now the universe is the same age everywhere, looks the same everywhere (no more lorentz contraction from the expansion), but we gave up the property of nothing being able to go faster than light globally. Local light speed is c relative to local observers who are moving away from us, or in other words, relative to "expanding space". But those observers can fly away from us at speeds well in excess of c.

Am I making slightly more sense now?

Re:Wait for the retraction

[Anonymous Coward]

The Doctor eh?

Re: Wait for the retraction

[Anonymous Coward]

This thread just became the embodiment of what those boffins are trying to achieve a discovery of. Ooooh.

Re:Wait for the retraction

[ceoyoyo]

I'm pretty sure it is. You can verify this for yourself by going outside twice a day. It's particularly evident if one of those times is, for example, around noon and the other is around midnight. You can also verify other types of movement by watching for the maximum height the sun achieves each day, and by checking it's position relative to the background stars.

More seriously, recognizing the Sun's movement relative to... the galaxy presumably, and the factors controlling that movement, is important to debunking the OP. Illustrative of this, someone made a very pretty, but physically inaccurate, rendering of the sun flying through the galaxy with the Earth trailing along behind it and uploaded it to YouTube in support of his "vortex gravity" theory: http://www.slate.com/blogs/bad_astronomy/2013/03/04/vortex_motion_viral_video_showing_sun_s_motion_through_galaxy_is_wrong.html.

Re:Wait for the retraction

[Trax3001BBS]

The thing about interpretations of quantum mechanics, is in the end, they don't make any predictive difference. They might make things fit together better in your head, or act as a muse when looking at the math, but in some sense they don't change the experiment. It is just a layer of abstraction on top of the math that works.

Thank you for that as I did see it as their interpretation of the experiment giving them the results they were looking for.

While I see the large lines just fine and lots of quantum physics principles I'm unaware of; entanglement being passed on to
another unrelated event seems a retraction is but a verifying experiment away.

I give...

[Anonymous Coward]

OK, it's official. Science and technology is accelerating so fast that I can no longer keep up.
Happy?

Re:I give...

[socceroos]

Subtle. Very subtle...

Re:I give...

[Black Parrot]

Not edgy, like the previous thread?

Re:I give...

[socceroos]

Can you have something that is both subtle and edgy at the same time? A superposition of the both states?

Re:I give...

[dougisfunny]

A subtle knife has quite the edge.

Re:I give...

[hairyfeet]

What I want to know is how entanglement doesn't crap all over relativity since changing one changes the other no matter the distance instantly. Also does anybody have a clue as to HOW the state is transmitted instantly, no matter the distance? Simple logic says there has to be SOME connection between the two going on but so far it seems no matter how far away they are from each other its still instant,so how is it getting there? Is it some sort of energy? Does space mean nothing in the quantum realm?

If they can figure out how to get this stuff down reliably though it does open up some cool applications, space communications for instance.

Re:I give...

[gagol]

Like, a useless thread is popular? Dang, I just hit a circular redundant conundrum!

Re:I give...

[Anonymous Coward]

What I want to know is how entanglement doesn't crap all over relativity since changing one changes the other no matter the distance instantly. Also does anybody have a clue as to HOW the state is transmitted instantly, no matter the distance?

Well, the key is to recognize that you don't need to transmit information to the other particle, because it is simply not true that changing one changes the other instantly. Indeed, there is absolutely no way to detect at one particle whether the other particle has been changed. All communication protocols using quantum entanglement require that you send some classical measurement results of your part of the entangled system (usually measured together with another system carrying the information you want to transmit).

So how can your observation affect your future observations on the other particle, if it doesn't change the other particle? Well, it changes you. You get entangled with the particle as you observe it, and thus also with the other particle. When you then interact with the other particle (or with anything or anyone who has directly or indirectly observed it), then this interaction is affected by your entanglement with it.

Re:I give...

[m.ducharme]

Entanglement does crap all over relativity. The two theories, while both showing astonishing degrees of experimental confirmation, are fundamentally incompatible with each other. Resolving this incompatibility is the most pressing project of current theoretical physicists.

Re:I give...

[fbjon]

No information is transmitted, the particles are merely correlated.

Wrong but sufficient analogy: If two balls bounce off each other in some random way and I take a look at one of them, I can tell what direction the other is going. Or if you like, by knowing the input velocities and masses, you can know the velocity of the other ball by looking at just one. The balls don't communicate, but some properties of both are "entangled".

That doesn't mean it's clear what exactly is going on and why it works, just that we're sure that relativity doesn't need crapping on for it to work.

Re:I give...

[Anonymous Coward]

It is more complicated than what people would classically picture for a correlation though. Actions taken on one particle after the separation can impact the correlation. It is simple to think that if you separate an up and down spin particle, that it is determined from the start which end gets the up and which gets the down. But then you start projecting the spin into a left or right state, and that classical view gets all messed up.

Re:I give...

[kermidge]

I don't know if your conclusion is so or not.

What I do know, having read the entire thread to this point, is that QM makes my head hurt and not in an entirely good way by trying to follow this stuff, and two other things: it all depends, and YMMV. Relativity, indeed.

Well, one more thing. There are some smart people here, even some nicely smart-aleck people, all trying to explain and help. Weird place, this, and weird people, we.

Re:I give...

[hairyfeet]

Don't feel bad pal, I'm just a humble bass player and PC fixit guy and a lot of this stuff flew past at Mach 5. I can see though why Einstein didn't want to believe in QM though, as frankly the rules as we know them seem to go Alice In Wonderland when it gets into the quantum realm. I mean its YOU and not the photon that is entangled? Its not instant yet every article we've seen says it is? Hell I still can't wrap my head around this stuff, what we need is a "Quantum Mechanics for dummies" video course.

Because frankly even when they try for "layman's terms" I feel like the guy in Event Horizon "Fuck layman's terms, do you speak English?"

Re:I give...

[hairyfeet]

Good, so its NOT just me then? Because I thought I was missing something, because it sure as hell looked from the numerous articles that they are getting instant change no matter what the distance which kinda does crap all over relativity. And does anybody have even the slightest inkling as to HOW the information is being transmitted? Is it energy, does space and distance no longer matter when you get to the quantum level?

Because while I've seen a lot of articles on entanglement I don't think I've even seen a guess as to HOW its happening, they merely state that it does.

Re:I give...

[kermidge]

Your last line gave me first good laugh of the day, thanks (I haven't seen the movie).

I'd rather have text than video. I get exasperated by sites that want to show you video for everything. If it involves physical methods - assembling a computer from parts, for instance - then yes, show me. Otherwise I prefer to read. By all means include pics and diagrams when useful.

Mach 5 indeed. Sometimes I think of it as Universe on pot for Einstein, and Universe on acid and falling asleep and having weird dreams for QM. (I consumed goodly amount of those way back when; it's not the best comparison maybe, but it's towards the way it looks like to me.)

Still, not having the maths, not spending enough time and effort reading on it, the whole quantum realm gives me a whole place of added wonder to our world, of awe, humble-making, puzzling stuff, lest we get too full of ourselves too soon.

Maybe. I think. Sorta.

Re:I give...

[hairyfeet]

You haven't? Dude if you like a good horror check it out, its damned good. Great cast, good special effects and a really great story IMHO.

And the reason I said video is that I have seen videos explaining things like dimensions that made it just SOOOO much easier to follow, like to show how multiple dimensions would be like to us used to only 3 they made a 2D creature in a 2D world and showed how even the concept of a third dimension would be so alien to it that it would have serious difficulty grasping the thought. If they could do something similar to show us how the quantum world works frankly i think it would be more illuminating than a book full of text after all a picture is worth a thousand words ya know.

Re:I give...

[kermidge]

I understand re vids, if they are done well. My preference is for text with whatever is needed by way of illustration, be it diagram, pic, or indeed, in-line vid.

I'll put Event Horizon on the list.

Re:I give...

[hairyfeet]

While I can understand a personal preference for text when it comes to some of these concepts I seriously doubt that anything less than video would work, I mean imagine trying to lay out a 27 dimension universe in flat pics, I really don't think it would be possible to do it justice.

And if you like a good, well written horror flick where you aren't sitting there going "Oh you SO deserve to die for being an idiot" then you'll like Event Horizon, I thought it was really well written with people acting more like people would act in such a situation.

Photon model broken

[Anonymous Coward]

'It's really neat because it shows more or less that quantum events are outside our everyday notions of space and time.'"

No, not really. You're simply see the macro effects of partial photons interacting, and unwilling to give up the idea of the discrete photon.

If all you can see (and measure) is a photons promotion and demotion of electrons, you an only see the fast shift of the big circles jumping around in this picture, not the slower smaller drift that is happening.
http://i.imgur.com/AUXb2N9.gif

Give up your photon model, it's based on a faulty understanding.

Re:Photon model broken

[Laxori666]

+1

Re:Photon model broken

[Anonymous Coward]

Well, so quantization of energy is wrong then? If you can have "fractional photons", then the Rayleigh-Jeans formula is completely correct. Never mind that it predicts that all blackbodies should be emitting radiation with infinite power.

Re:Photon model broken

[VortexCortex]

The world is made of 4 basic elements, earth, air, fire, water.... No, scratch that, there are a bunch of elemental stuffs, the most holy of which is quicksilver, the universal element... Wait, no, there are over a hundred chemicals with different properties. Ah, look, see, there are atoms, you know, and inside these atoms you have electrons, protons, and neutrons -- See, that's what gives the atoms their properites -- And, wait, the sub atomic particles are made of Quarks, and -- No, there's a zoo of particles, and fields and they all interact in these little quantized packets / waves, Quantum Physics -- No, wait the quanta.......

The rabbit hole is very deep indeed. Better tools show us finer structure. I agree. It would be exceedingly arrogant and foolish to think of light as "photons". We have only approximations, and they are always a bit wrong.

Re:Photon model broken

[10101001 10101001]

Well, I tend to think of quantum mechanics as proving the universe functions on call-by-need, with faster than light being the lack of support for mutation. Entangling then is really just call-by-need evaluating out a circumstance backwards far enough to note that when two waves/particles/whatever were at the same place, they had to have certain exclusionary properties (for the article, one photon was polarized vertically and the other horizontally) which cause the interpretation of entanglement.

Of course, all of the above says nothing of the how or why of it. And no doubt, I'm likely far off in really understanding on quantum mechanics. But, it at least helps me better understand it.

Re:Photon model broken

[Pseudonym]

The world is made of 4 basic elements, earth, air, fire, water...

Today, we call them "solid", "gas", "plasma", and "liquid" respectively.

Re:Photon model broken

[maxwell demon]

Actually, there's a very simple interpretation of this experiment which doesn't need entanglement over time at all:

First, you create a normal entangled pair (no over-time entanglement involved).

Then, you measure one of the photons, breaking entanglement. The other particle now has the corresponding state. If we were to measure it immediately, we'd find the correlations with the first photon we use to detect entanglement that was present before the first measurement.

But we don't immediately measure it, but we use a second pair of entangled photons to quantum-teleport it. Note that there's no entanglement swapping going on here, because there's no longer entanglement in the first photon. It's just normal quantum teleportation (well, actually entanglement swapping is also just quantum teleportation of an entangled particle). Of course the teleported photon has the same state as the non-teleported.

Now the teleported photon is measured. Of course we find the correlations with the first-measured photon. That doesn't mean this photon was ever entangled with the original one.

Re:Photon model broken

[bug1]

Dude, its, like, totally real, man.
The photon is chillin with the physicists at an event in the parallel university after it went through teh wormhole.

Can i have my grant money now ?

Re:Photon model broken

[Anonymous Coward]

Ya, unless you've done graduate level quantum physics, I think you need to STFU.

Re:Photon model broken

[Anonymous Coward]

It really is amazing the sort of pseudo-intellectual drivel that Slashdot finds to be "insightful".

Re:Photon model broken

[tonywestonuk]

I believed as you did. Then I read this http://quantumtantra.com/bell2.html - Its like Quantum physics , without the maths, and for the it literate.

Changed my ideas on what QM was all about.

Go read it. Seriously.

Re:Photon model broken

[tonywestonuk]

Oh, once you've read it, if you can code, go try making a program to simulate whats going on.... Try it. At some point you'll come to the conclusion that something really weird is happening.

Re:Photon model broken

[The Mighty Buzzard]

And Leeloo.

Re:Photon model broken

[Anonymous Coward]

I've wondered if quantization is an effect of measurable interactions by necessity using the same amount of energy implied by, in say the case of a photon, the its frequency. Partial photons would be able to explain a lot about quantum physics without resorting to multiple worlds theorem or people yelling "shut up Copenhagen works fine because I don't understand what's wrong with it!" I mean, even something as basic as the double slit/single photon experiment becomes easy to understand, the "photon" is split into two waves which interfere with each other, done.

Always good to see others thinking along the same lines.

Re:Photon model broken

[Anonymous Coward]

I dunno nothing about this physics stuff, but I can tell you that you are wrong.

I just took a dump, and it sure wasn't solid or liquid. It was a solid liquid with some gas.

Re:Photon model broken

[Nefarious Wheel]

Entangled Object Oriented language? Certainly you'd need parameter overloading.

Re:Photon model broken

[Anonymous Coward]

Well, yes and no. You're not wrong but the rules that govern our day-to-day lives are very different from the rules of the very small. We don't really know what the link between them is and even if we did, it doesn't alter that basic fact. The rules are different. No amount of model massaging is going to change that.

Re:Photon model broken

[kfsone]

I've noticed in recent years that the verbiage used to describe quantum physics has changed; when I was a kid, they would use passive words that made it sound like awareness of a state caused it's destruction rather than today when they seem to be more clear that some states require interaction-with-side-effects (measurement or interference) to obtain the information. Yay progress.

That gif reminds me of a thought experiment: Imagine a person living in a 2d universe that happens to be on a flimsy, square piece of tissue paper loosely attached to a square, wire frame. The piece of paper is placed in a rocket and launched into space. Now it's at rest in a pressurized capsule, and for things are normal. The 2d man is running around kicking a ball obeying 2d-physics in his 2d-universe but subject to external forces from the surrounding 3d universe. So what will he experience when someone taps or nudges the frame and sets his 2d-universe rotating or drifting? How will he explain why sometimes the ball seems to experience more or less friction? If the paper ripples enough, will the ball seem to blink out of existence?

In 2011 they speculated the universe might have a slight spin to it. But what if it is also moving and/or turning/rotating on/along one or more axis. How would we perceive that?

Re:Photon model broken

[Anonymous Coward]

Multipass!

Re:Photon model broken

[rts008]

How would we perceive that?

Normal folk would look outside.

Half the /. bunch would trudge up the basement stairs and search for a window.
The other half would find an online camera to check outside.

All joking aside, you made an interesting comment.
I have also suspected the universe has to be moving in odd ways.
I base this on the behavior of surrounding space near a supernova, the odd nebula formations seen in the universe, and the expansion of said universe observed...and they say weather, or nuclear explosions are hard to model!

Re:Photon model broken

[cripkd]

OMG, is that a photo of how light really looks?

Re:Photon model broken

[cripkd]

Best comment for today.

Re:Photon model broken

[Anonymous Coward]

So you are chilling with photons instead of working? Sorry, no grant money to you. :-)

Re:Photon model broken

[Anonymous Coward]

Sure, with a flash!!!

Re:Photon model broken

[Anonymous Coward]

you already have it, its called a variant...!

Re:Photon model broken

[Anonymous Coward]

You know what, I failed physics for making that very point.

Well, I failed because I wasn't very good at regurgitating the shit I was being fed and that just happened to be the moment I realised I knew more than my teacher.

Thanks /. I've always been to afraid to make the point again in learned circles and you've just dismissed that fear =)

Re:Photon model broken

[Kjella]

You think the ancient Greeks didn't know about snow melting to water, water vapor from boiling or dew from moist air? The four elements are their first attempt at the periodic table, they did not confuse elements and states. Though I suppose fire was way off the mark.

Re:Photon model broken

[Anonymous Coward]

Personally, I find the 4-5 elements of wind, fire, water, earth and space to be more practical approximations in day-to-day understanding of events.

Re:Photon model broken

[khallow]

You're simply see the macro effects of partial photons interacting, and unwilling to give up the idea of the discrete photon.

Where? Doesn't the observation have to support your claim first?

And it's worth noting the current quantum models already have a couple of senses in which photons can be partial. First, you can take energy away from a photon. Second, you can entangle a photon state with a non-photon state (such as the two slit experiment where a photon can entangle with itself while passing through two narrow slits, but not if you try to observe which slot it passed through).

Re:Photon model broken

[Anonymous Coward]

How the fuck is this +5 insightful? The whole point of these entanglement experiments is to show that quantum mechanics predicts their results perfectly, despite our faulty, but hard to shake, classical intuitions. Your post reads like someone who got all of their knowledge of quantum mechanics from some horrible pop sci book.

Re:Photon model broken

[Anonymous Coward]

Winnnn!!!!

Re:Photon model broken

[Anonymous Coward]

Do you have more information about this? Where is that image from?

Re:Photon model broken

[Anonymous Coward]

In some state the program is already done. I just need to make sure I open it at the correct time.

Re:Photon model broken

[thoromyr]

This is based on a broken (modern) understanding of ancient philosophy. I had the good fortune to read Vitruvius Ten Books of Architecture back in high school and it taught me an important lesson: never rely on some modern person's lazy interpretation and whimsical assumptions about what the ancients did or thought. If you do, you end up with nonsense like knights being hoisted into their saddles and mixed up ideas of elements.

In brief (and very much from memory) none of the four elements had more than a philosophical resemblence to the "substance" named. Rather, they were terms for properties and just a way of describing objects in the world around them. For example, a wood that was light but brittle would have more 'air' than 'earth' (relative to a hardwood). Vitruvuius talks about this in terms of selecting wood for construction and I remember a point about a particular tree found in Germania that was resistant to being ignited and was thus recommended for shingling roofs. I don't recollect what the elemental composition was described as (high school was a long time ago), but it was just an empirical description phrased in terms of the four elements.

What do they teach kids in school these days? :)

Re:Photon model broken

[volpe]

I But what if it is also moving and/or turning/rotating on/along one or more axis. How would we perceive that?

Perhaps as a cosmic centrifugal force that causes galaxies to fly apart from each other, interpreted as a cosmological constant causing the expansion of space itself? Oh, wait...

Re:Photon model broken

[cyberchondriac]

There is some debate as to whether fire can qualify as plasma (most think not, as there's no inherent charge), but.. close enough I guess.
If Aristotle had only claimed Earth, Air, Lightning bolts, and Water instead...

The fifth element was typically quintessence/spirit, but I'd happily substitute Leeloo!

Re:Photon model broken

[Anonymous Coward]

Those are states of matter. Not elements.

Re:Photon model broken

[Anonymous Coward]

Oh, once you've read it, if you can code, go try making a program to simulate whats going on.... Try it. At some point you'll come to the conclusion that something really weird is happening.

I may lack the necessary imagination, but how would one begin to code such a simulation?

Re:Photon model broken

[Anonymous Coward]

Why can't we then transmit superluminal messages by using the rate of error as the transmission medium?

Re:Photon model broken

[Yourself]

And if you'd had habaneros with lunch, there would also be plasma (fire).

Re:Photon model broken

[nickersonm]

The substructure of the universe regresses infinitely towards smaller and smaller components. Behind atoms we find electrons, and behind electrons, quarks. Each layer unraveled reveals new secrets, but also new mysteries.

- Academician Prokhor Zakharov, "For I Have Tasted the Fruit"

Re:Photon model broken

[Anonymous Coward]

Best comment of the week.

Re:Photon model broken

[david_thornley]

partial photons

Okay, how well have you verified that your model predicts the photoelectric effect, the properties of black body radiation, and the operation of lasers? Does it predict these as well as the theory that physicists have carefully verified over the last century? (There's other phenomena to explain, but these are the ones that I thought of first.)

On the exceedingly likely assumption that it doesn't, how do you get (+5, Insightful) for the rough equivalent of telling us how humans are descended from bananas?

Re:Photon model broken

[HiThere]

Or, from a different prespective:
Models, Logic, Desire, and Motivation.

P.S.: Single words don't map the concepts well, but the alchemists were as much philosophers as chemists (with different individuals leaning in different directions).

Re:Photon model broken

[HiThere]

Are you certain that it can't be done?

Nobody's been able to do it yet, but that's not proof. I've heard arguments as to why it's impossible, but I'm not physicist enough to understand them enough even to say whether they were convincing or not. The last time I tried to understand that area there was a general agreement that it couldn't be done, but there were several qualified physicists that felt that it hadn't been proven.

Re:Photon model broken

[Anonymous Coward]

The limitations about using quantum entanglement for communication falls out pretty quickly from math and some of the basic axioms used in quantum mechanics. Of course it could be possible, but that would mean it is either something fundamentally different than quantum entanglement, or that quantum mechanics is fundamentally wrong (as opposed to misapplied or only partially wrong).

And to the previous poster... I don't think you would be able to know your errors without receiving communications from the original sender classically.

Re:Photon model broken

[Anonymous Coward]

Chicken!

Re:Photon model broken

[Anonymous Coward]

But, dammit, there are turtles at the bottom

Re:Photon model broken

[tonywestonuk]

Replying to an anonymous coward.... :-/

Ok, You would perhaps create a class that is your entangled pair source. It will have a method, getEntangledPair(), which would pass back 2 photon objects.
There would be a SPOT meter class, that could compare the polarity of 2 photon objects, and give a '0' or '1'. its up to you how you code them.

Now, the trick is, to try and make your program work, and produce the results of the experiment, *without* having any communication between the photons objects (via, say some global / shared variable).
The problem Is, I cant do that. I tried. I failed. The *only* way I can get my program to produce the same results, is by having such a hidden communication mechanism. According to Bells proof (mathematical), its impossible to do this.....though, I dont understand the maths, I have an appreciation why I cant make it work.

there is another way of making it work, however, without using hidden communication....

Re:Photon model broken

[tonywestonuk]

....that is, getEntanlgedPair() returns an array of photon pairs, not just 1. Each of those photons has been preconfigured to be set at a particular polarisation.... then, the spot meter is made to only look at the photon pair its orientated to look at. this way, everything can be precalculated up front, and stored within the photons.

the problem is, there is only a limited amount of angles you can precalculate for. you could do 360 degrees of a circle..... BUT, the spot meter could be configured to at a half of a degree..... Its impossible to precalculate all outcomes (unless you happen to have a quantum computer!!),

Re:Photon model broken

[tonywestonuk]

If reality is like this..... then, a photon isn't like a shiny ball traveling through space....but instead, an infinite array of photons all having a slightly different properties, and all having zero energy, but as a whole having some energy.

only when this thing interacts with something, at that point, the correct photon is selected out of the array, and 'becomes' a particle.

I wonder if.....maybe its not a single infinate array, but rather a stream of photons..... yet, practically all those photons do not interact with anything. only the ones that happen to be preconfigued to be able to be filtered through the spot meter work. The rest of them just never show up.

Re:Photon model broken

[Anonymous Coward]

Thar or you use the same matrix and vector notations used in quantum mechanics calculations, which can represent such states exactly...

Predictions for quantum processes are not impossible to predict on classical computers (or be hand...), they can just be slower (in terms of computational difficult class, not necessarily absolute time for simple examples).

Re:Photon model broken

[tonywestonuk]

No.....you cant do this, without having a communication link between the two photons.

The correlation of the photon polarisation is defined as the cosine of the angle between the spot meters (Haha - Easy Maths c=Math.cos(spot1.getAngle() - spot2.getAngle()) . So, in code, both photon objects *must* have a reference to each other, in order to find the angle to feed into the equation. In reality, this means the photons must communicate using "spooky actions at a distance"

Its is not possible to represent the state of a quantum object, using local variables alone. This is what Bell proved.

The alternative, is there is no quantum object, there is no photon. But instead an infinite array of objects, all having slightly different local state.

Re:Photon model broken

[Anonymous Coward]

The math done that predicted the existence of entanglement and predicts quite accurately (and exactly in some cases) the outcomes of different entanglement and other quantum systems works just fine with a classical computer (... or classical paper and pencil...). You could easily represent the entanglement with a finite sized state array. It is not a violation of Bell's inequality, because such a representation is neither local, nor hidden variable. It is easy to see when looking at examples of bra-ket notation, because there are many cases where the vector space of states has a finite dimensional basis.

Science

[MyLongNickName]

At some point, science just got too weird. We had this nice model of the universe with atoms, some laws of motion and thermodynamics. The universe was basically a giant billiards match. It made sense. It was easy to explain. Then we get into quantum mechanics and everything is crap shoot. Multiple universes. Particles that behave differently when being observed. Spooky action at a distance.

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

Re:Science

[Nyder]

...

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

I'm sure some of the various religions will be glad to join your thinking (if they aren't already there).

Re:Science

[VortexCortex]

At some point, science just got too weird. We had this nice model of the universe with atoms, some laws of motion and thermodynamics. The universe was basically a giant billiards match. It made sense. It was easy to explain. Then we get into quantum mechanics and everything is crap shoot. Multiple universes. Particles that behave differently when being observed. Spooky action at a distance.

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

That's what you said last time. Look what it got us? We're back to quantum physics AND we have nuclear weapons. Are you really ready to risk Universe hopping again?

Re:Science

[Anonymous Coward]

Nature and nature's laws lay hid in night;
God said "Let Newton be" and all was light.
It could not last; the Devil shouting "Ho!
Let Heisenberg be!" restored the status quo.

Re:Science

[louzer]

When history of these times are written scientists of quantum mechanics today would be considered like the scientists of planetary epicycles and scientists of Descartian physics.. There will be a simpler causal interpretation of the evidence which supports quantum mechanics without all the magic: De Broglie–Bohm theory.

Re:Science

[Anonymous Coward]

At some point, science just got too weird. We had this nice model of the universe with atoms, some laws of motion and thermodynamics. The universe was basically a giant billiards match. It made sense. It was easy to explain. Then we get into quantum mechanics and everything is crap shoot. Multiple universes. Particles that behave differently when being observed. Spooky action at a distance.

There is no such thing as "observation". The universe completely lacks a "read" operation.

What we think of observation is *always* upon on closer inspection interaction. Any concievable measuring device or method of observation functions by disrupting its environment. e.g your eyes don't "see" they absorb photons produced or reflected by surfaces.

Spooky correlated behaviors are just a particular transaction semantic.

Re:Science

[Black Parrot]

The latest Scientific American has an article about a newish bayesianized quantum theory. To the limited extent that I understand it, the wave function is just the bayesian priors - what you think before you collect the evidence. The only thing that collapses when you measure something is your ignorance about the state of the universe.

Re:Science

[Anonymous Coward]

Then I guess you can go back to vacuum-tube-powered computing? The humble solid-state diode and transistor are based on quantum physics (though the common derivation uses a "quasi-classical" simplification to make the math tractable) even in the "classical" computers since the 1960s.

Even there, though, and you're only down to the era of Maxwell, not Newton. If you want to return to Newton's ideas, you need to crank up a Babbage machine!

Re:Science

[Anonymous Coward]

Particles that behave differently when being observed.

This is much easier to understand when you realize that our "observations" of quantum events is less like looking at something, and more like poking it with a stick.

Re:Science

[fightinfilipino]

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

the Republican Party? large swaths of the American Bible Belt? Scientologists? Liberal Arts majors? Michio Kaku?

Re: Science

[Anonymous Coward]

Sounds Great

posted from my iTelephone

Re:Science

[maxwell demon]

Actually de Broglie-Bohms unobservable particle trajectories are the exact equivalent to the epicycles: Additional complications, introduced to save certain assumptions on the world (epicycles: only circular motion, with the earth in the center; Bohm trajectories: movement of well-localized particles in space).

Also, de Broglie-Bohm is incompatible with special relativity.

Re:Science

[Anonymous Coward]

Who's in?

I'm in.

...Well, I think I am, but thanks to quantum physics I might actually be out (tunneling), or even both in and out at the same time (superposition). So maybe asking me isn't the best option.

You could to ask my friends what they think (complementarity) because I'm sure they all know me well enough to say (wave functions). Oh, but while they could tell you where I am, they wouldn't know if I might just up and change my mind (uncertainty principle).

Re:Science

[Anonymous Coward]

What makes you think so?

We have models for how things work. Little formulas that give the correct answer within a certain range of conditions, but don't represent the fullness of what's going on. That's normal and easily understandable, right?

But all of our senses, and for that matter our minds, evolved to catch deer and dodge tigers. And so they create this mental model of the world around us, and we arrogantly assume that that model is complete and shows the world as it really is. Time goes this way, things are exactly one place at each moment, etc. It's a useful model, and I'm certainly not suggesting we abandon it (as if such a thing is even possible). But it's silly to think that the universe just so happens to work in a way that our brains would find intuitive or simple.

Re:Science

[Anonymous Coward]

fuck yes, I'm in.

Re: Science

[Anonymous Coward]

At one point life where easy to understand.
What we saw was what was shown.
What we heard was what was said.
Then we discovered girls.

Re:Science

[Anonymous Coward]

Slidersssss.

Re:Science

[jamesh]

At some point, science just got too weird. We had this nice model of the universe with atoms, some laws of motion and thermodynamics. The universe was basically a giant billiards match. It made sense. It was easy to explain. Then we get into quantum mechanics and everything is crap shoot. Multiple universes. Particles that behave differently when being observed. Spooky action at a distance.

Douglas Adams had some very wise words on this subject, the implied conclusion being that scientists studying the universe are making it more complicated.

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

Maybe you could go all the way back to when the universe began, 6000 years ago? But don't look back or you might get turned into a pillar of salt or something like that.

Re:Science

[L4t3r4lu5]

Let Heisenberg maybe!" restored the status quo.

Re:Science

[gagol]

Aren't most of them stuck at this flat earth thing and trying to convince the rest of the town their flat earth theory is the only one worth worshipping?

Re:Science

[Warbothong]

"I find X to be strange" is another way of saying "I'm pretending that I live in a magical, X-free fantasy world.". There is no such fantasy world and never has been. Nature doesn't care if your brain is mis-configured.

When we get a result that's unexpected, we have an opportunity to deepen our understanding. That's science. When we get a result that's "strange", we're being contrary to our own knowledge. That's not science; I'd say it's more like religion.

Re:Science

[peragrin]

Science is always weird. 100 years ago atom weren' known exist. electricity was some wierd etheral vapor. besides atoms and laws of motion and thermodynamics only cover somethings. we kept noticing funny results at the edge cases. The farther down we go the funnier the results get.

Eventually we will find out that all this quantum stuff actually makes sense and the funny properties are the results of us using planets the size of mars to figure out where the earth is. (relatively speaking).

Re:Science

[chris.alex.thomas]

the deeper I get into this topic the more I see the universe as an energy field, clumped together in places to form atoms, but they are not separate entities, but merely an observation or easy to facilitate way to see how the field is distributed.

Re:Science

[houbou]

Ok, then bye bye warp drives! :)

Re:Science

[Anonymous Coward]

Obligatory:

There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.
                                                                                  –Douglas Adams

Re:Science

[Anonymous Coward]

No. That's the lie your chosen religion tells you so that you feel superior to those "other people", and then you don't care what happens to them.

"Hey, who cares if they're being persecuted, they deserve it. They're flat earthers, after all."

Re:Science

[Splab]

Except no one actually believed in the flat earth thing, it's a myth that we thought the world was flat...

Re:Science

[fritsd]

That doesn't help.. Bayesian statistics is difficult to wrap my head around..

<shame>
I have trouble enough understanding the Monty Hall goat-deselection problem without enumerating the solution space..
</shame>

Re:Science

[sanman2]

Yeah, I think quantum physicists delight in making their field look as cryptic and mysterious as possible. That's why they go out of their way to use the kinds of words that can easily be misunderstood, and create more heat than light.

Re:Science

[gstoddart]

"I find X to be strange" is another way of saying "I'm pretending that I live in a magical, X-free fantasy world."

No, it means quantum mechanics is some weird shit that most people can't really get a good handle on without a faulty analogy involving a cat.

And, if it skips past our understanding of time a little (like entangling two things which don't exist at the same time), then it gets into some really weird shit that most of us can't get a good handle on.

Re:Science

[rafpayen]

80+ Years ? Actually there hasn't been that much progress in quantum theory since 1933.

But let's say we go back to 1890. Now, there is a praise for to the first guy to make a patent for a system allowing simultaneous synchronisation of all the clocks of all the train stations of the realm. You can propose any kind of system, which will be reviewed by a clerk in Geneva. Beware: the clerk is intelligent, has read Poincare, and sometimes has mystical visions where he is travelling on a light ray.
(And also, some people would really like to explain why a black body doesn't emit infinite radiation).

Re:Science

[Anonymous Coward]

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

I believe that the current US Republican party is supporting that position.

Re:Science

[IRWolfie-]

Or perhaps complex fields require complex terminology, but I guess that doesn't fit with the "Scientists make it look hard to fool us" type viewpoint.

Re:Science

[IRWolfie-]

The language of physics is math, and to get a handle on quantum mechanics you need math and lots of it. Unfortunately the general population is mostly mathematically illiterate (along with many slashdot readers), so quantum mechanics will always be meaningless to them.

Re:Science

[ceoyoyo]

Thanks, but I like having things like modern electronics. I think there are some Luddite groups that might like to have you though.

Re:Science

[Anonymous Coward]

A bit more collapses. Have you noticed the physicists remarks lately that the universe is nonlocal? Precisely they are saying the entire universe is nonlocal. That leaves observers like you or I outside of the universe as if we arew looking at a high tech display. Matrix stuff for sure.

Re:Science

[steelfood]

The only thing that collapses when you measure something is your ignorance about the state of the universe.

Could it collapse differently if I measured it than if you did, assuming neither of us knew the measurement beforehand?

Re:Science

[Anonymous Coward]

Actually the Monty Hall selection problem is quite easy.

You choose a door of three. The probability of choosing the right door is 1/3, obviously.

Then the show master opens another door which is goat door. He will always open a goat door (that's an important part; for example if he would always open the winning door whenever given the chance, you'd be a fool to change, because then the only reason he opened a goat door would be because you've already chosen the winning door). Since you already knew he would open a goat door, you get absolutely no additional information about whether you chose right or not, so the probability that you chose right remains 1/3.

However you did get the information that the winning door is not the one he has opened. So if you chose wrong in the beginning, then obviously the winning door must be the only remaining one.

So your situation is this: If you chose the winning door from the start (probability 1/3), you obviously shouldn't change. If you didn't choose the winning door from the start (probability 2/3), you obviously should change. Since the latter probability is larger, you definitively should change.

What people generally fail to take into account is that the show master gives you no information about whether you've chosen the winning door because he always opens a goat door. If he instead would not know the winning door himself and randomly opened one of the doors, the situation would be different, because then the fact that the door is a goat door increases the probability that you've chosen the winning door (because if you chose wrong, there would have been a probability of 1/2 for the show master to open the winning door), and then it indeed wouldn't matter whether you change the door or not.

Re:Science

[Anonymous Coward]

The second half of your post doesn't follow from the first half at all.

Re:Science

[Anonymous Coward]

Quantum physics is not he field I work in any more, but that doesn't matter too much as the physicists there seemed to act pretty much like they do in other fields. I don't think I've bumped into anyone trying to make things esoteric on purpose. In fact, many of them go to great lengths to try to explain and teach their work and field. Part of teaching things like physics though is to teach people what is significant and what is not, to point out to them that some things that look like minor semantics actually can make a big, important difference and a clear distinction needs to be made. Hence the large amount of jargon and specific meanings to certain words. No every physicist is like that, although the worst I've been around amount to them just not caring if nonphysicists got it or not, not enjoying lack of understanding.

Re:Science

[Anonymous Coward]

Ok, then bye bye warp drives! :)

You have a warp drive? Pics or GTFO.

Re:Science

[Patch86]

And yet:
http://en.wikipedia.org/wiki/Flat_Earth_Society

Re:Science

[Anonymous Coward]

When we get a result that's "strange", we're being contrary to our own knowledge. That's not science; I'd say it's more like religion.

Wrong, wrong wrong. You should read Isaac Asimov, and I'm not talking about his science fiction, but his science nonfiction. Dr. Asimov was a biochemist who did cancer research at Boston University, and a famous quote of his went "The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's strange!'"

Confirming a throry is satisfying, but getting a strange result leads to more valuable research. Pure science, not religion at all.

Re:Science

[david_thornley]

If the wave function is a result of necessarily limited knowledge about the real state, that would imply there was a real state, and that sounds an awful lot like a hidden-variable theory. Hidden-variable theories aren't necessarily wrong, but there's a pile of experiments that it would have to be compatible with somehow. Do you remember if they addressed this?

Re:Science

[HiThere]

I don't believe they did. OTOH, the theory is still in the development stage, so perhaps that's just in a part they haven't seen yet.

Re:Science

[snadrus]

Mis-configured is an interesting thought. Typically things seem exceedingly complex if they're being looked-at incorrectly. The perception of incorrect currently is that our tools aren't sensitive enough for the direction we are going. But if in-fact better explanations exist the universe's properties, then building sensitive tools may actually be creating complexity in the sense that we are looking in the wrong place.

For example, alternative theories of various fields (electric universe) are slightly or mostly disproven, but few-to-nobody is trying hard to write exceptions & make them work like we are doing with the current models.

In software, if the 'wrong' abstraction is used to build-out a concept, the result can be far more complex than what's necessary for the task. Like a math 'proof' with too many steps that doesn't go the right direction & still is looking for partial credit.

Re:Science

[Anonymous Coward]

Science wasn't that backward 80 years ago. Evolution was a well established consensus, the value of pi was well known, there was little argument over the age of the earth and the universe...

Basically, the bible belters want to move back to a time before science existed at all. Certainly pre-Christian.

Re:Science

[Agent0013]

Except they proved that it is not due to unknown variables like you are stating. I think the experiment where the two photons pass through a half-silvered mirror and cross to two detectors. Non-entangled photons travel to random detectors while entangled ones always go to the same detectors. If you put a polarization twist into one of the photons so you can see which one took which path they go back to the random paths. If you remove the twist after they have passed through the half-mirror, so they have already decided if they will go to the same detector or not, they still always go to the same detector. In a certain way this experiment shows that time is unrelated to the entanglement, or at least the behaviour of the photons. It seems to our mind that they made the decision before the twist was removed so they must have gone back in time to change their path. The way I understand it is the entire path of both photons is part of the quantum configuration and it resolves at the detector so it doesn't matter that the twist removal was after the branching decision.

Re:Science

[Anonymous Coward]

It still works...only at Newtonian - i.e. human - scales. As humans we are hard-wired to understand only things at those sort of scales so anything that is extra big or extra small can only be understood by attempting to apply the human-scale template - that's why the billiard ball / solar system / atomic structure template held up so long - but it didn't make it right. It just happened to be approximately right until you got down to the levels of precision needed at the massive and tiny ends of the scales.

Re:Science

[kalqlate]

I believe that de Broglie-Bohm theory also puts things similarly.

"doesn't exist"

[girlintraining]

Hey guys, Einstein just called me using GravePhone(tm) and he had the following to say:

"Okay, maybe God does play dice, but I still stand by the law of conservation. God doesn't just make shit up. Now if you'll excuse me, Aristotle wants some one on one on the basketball court."

Re:"doesn't exist"

[Anonymous Coward]

Erm... God not making shit up is called the law of conversation...

Re:"doesn't exist"

[Alomex]

Einstein would never play BB with Aristotle. The latter was a philosopher and a really bad one at that.

Bert hangs out with Isaac, Archie (medes), Leo and the rest of the physicist gang.

Re:"doesn't exist"

[Samantha Wright]

Aristotle was (almost) Newton's direct predecessor in understanding of the physical world; it is certain that Newton would have read his writings due to the Renaissance. Newton would be annoyed if he were left off the court.

Moreover, while we don't know much about Aristotle's personal life, Socrates was formerly a soldier and Plato was a seasoned wrestler. It was typical in golden-age Athens for the intellectual to also be physically fit.

In short, the physicists would get schooled, much like the jive suckers of old.

Re:"doesn't exist"

[Alomex]

Aristotle was (almost) Newton's direct predecessor in understanding of the physical world;

Pfffft. Aristotle made up stuff while "thinking" about the world. This is not science.

The predecessor of Newton is Galileo, who brought experiments into physics. I.e. do not cogitate that heavier objects fall faster, go out and measure it instead.

it is certain that Newton would have read his writings due to the Renaissance.

Of course, and proceeded to ignore them for the rest of his career. Essentially nothing Aristotle did stood the judgment of time. Compare this with Archimedes, Copernicus, Galileo, and Newton, whose theories have been superseded but remain as good approximations to this date.

Re:"doesn't exist"

[Samantha Wright]

Pfffft. Aristotle made up stuff while "thinking" about the world. This is not science.

This is an extremely childish and anachronistic viewpoint. Newton entertained many unscientific notions alongside those which bore fruit; the scientific method was an invention of his generation. We owe an incalculable amount of our understanding of the universe to philosophy, and selective ignorance of history changes nothing.

Above all else, the classical scholars gave the Renaissance scientists an intellectual authority with which to question the world; it is absolutely absurd to suggest they were ignored. Aristotle's impact went much further than the details of his assumptions about physical motion.

More to the point, however, they would still be much better basketball players.

Re:"doesn't exist"

[Anonymous Coward]

Someone seriously needs to film this Einstein vs Aristotle match and put it on YouTube.

Re:"doesn't exist"

[girlintraining]

More to the point, however, they would still be much better basketball players.

You guys really over-thought this. I picked Aristotle because he's a famous scientist. No other reason.

Re:"doesn't exist"

[Samantha Wright]

...but he was a philosopher, not a scientist! D:

Re:"doesn't exist"

[sjames]

Pfffft. Aristotle made up stuff while "thinking" about the world. This is not science.

Don't sell him short. He was missing the tools we have now, including the formulation of the scientific method and observation. OTOH, without Aristotle and his contemporaries getting the ball rolling on thinking about the world and how it works, Newton would have stuck with theology.

Re:"doesn't exist"

[Anonymous Coward]

How about logic?

Measurement error

[PedroV100]

This is probably a measurement error that the media will make sure to overhype again. I wonder how many paradoxes you can create if it were true. Cats can prey on the grandparents of the scientists of the future before the scientists are conceived. Yet these scientists may have the control over the cat's life/death before the cat has the chance to kill anyone.

Re:Measurement error

[Anonymous Coward]

The problem is that entanglement doesn't actually allow you to send information anywhere using it. It does weird things, but you can't actually cause one particle to change state the way you want it to. Trying to alter the state breaks the entanglement. So there is no violation of the principle that information can travel faster than light, or backwards in time.

It is useful in quantum communication as a source of shared randomness, because the states are shared in a known way, but I can't control the state of the particles.

Re:Measurement error

[maxwell demon]

No, it's not a measurement error. It's exactly what you'd expect from such a setup, without assuming entanglement over time. However, if they had described this experiment as what it actually is, a standard Bell measurement where one of the photons was quantum-teleported before measuring it, but after having measured the other photon, I'm sure it would not have generated much interest.

Re:Measurement error

[maxwell demon]

Oops, I just notice I mixed up the terminology: It's of course not a Bell measurement (although a Bell measurement is involved in the teleportation/"entanglement swapping" step), but the measurement of a Bell inequality violation.

Re:Measurement error

[JimFive]

The problem is that entanglement doesn't actually allow you to send information anywhere using it.

Doesn't it let you send the one bit of information "I have broken the entanglement"? If so, then that would send information faster than light.
--
JimFive

Re:Measurement error

[Anonymous Coward]

No, entanglement does not send that information. If you are dealing with a one bit situation, so there are only two outcomes, then before entanglement is broken, you have a certain chance of getting a 0 and a certain chance of getting a 1 (lets say 50-50, but could be 25-75 or whatever in a more complicated setup). Once entanglement is broken, you still will have the same chance of getting a 0 or 1. The only difference now is that the you will see a correlation with the number the other end got once they send you their results.

Lets assume you have a 50-50 chance of getting a 0 or 1. Someone makes an entangle system, such that both ends always get the opposite value, but it is still based on this 50-50 split of a 0 or 1. Alice at end one makes a measurement, she is not able to choose the outcome, and will get 0s half the time and 1s half the time. Bob at the other end also makes measurements. If he makes them before Alice, he gets the 0 half the time, and a 1 half the time. If Alice had made the measurement first, since she gets 0 half the time, Bob gets a 1 those times, and she gets 1 the other half of the time, so Bob gets a 0 those half of the times. So Bob still sees 0s half the time and 1s half the time. He has no idea what Alice got until she tells him, so he has no way of telling if any particular 0 or 1 he got was actually the result of entanglement, or happens before or after Alice makes her measurement.

Re:Measurement error

[Agent0013]

The only way you know if they are entangled or not is to communicate at slower than light speeds as to whether your measurements match up or not. If you broke the entanglement the other person could not tell until you talked to them to tell them you did.

I can has closed time loops?

[Anonymous Coward]

Can we use this trick to create closed time loops?

B sends message to A using ordinary speed-of-light (or even speed-of-sound) communications.
A sends the message back in time to B, via entangled photons, since B can measure his photon before A's photon ever existed.

Plot twist: B never told A that the original message came from the entangled photon experiment, and A never told B that his message came from B.
How is mesagge fromed?

Re:I can has closed time loops?

[Black Parrot]

Why not just take a little piece of paper, and write "see other side" on both sides?

Re:I can has closed time loops?

[Anonymous Coward]

Because that's just a "time waster"; it's not related to the time loop paradox that creates information from nothing.

Re:I can has closed time loops?

[0xdeadbeef]

I dunno, but I hope this means someone builds a Predictor.

http://www.nature.com/nature/journal/v436/n7047/full/436150a.html

Re:I can has closed time loops?

[maxwell demon]

Can we use this trick to create closed time loops?

No.

B sends message to A using ordinary speed-of-light (or even speed-of-sound) communications.

OK, no problem in this step. ;-)

A sends the message back in time to B, via entangled photons, since B can measure his photon before A's photon ever existed.

No. You cannot send a message just using entangled photons. You always have to send classical information along in order to communicate. So to use entanglement for sending information into the past, you'll first have to solve the problem of sending classical information into the past.

Think of the entangled photons as being an encryption key. It doesn't help you if you get the encryption key, as long as you don't also get the encrypted message.

Re:I can has closed time loops?

[Anonymous Coward]

No problem. Transmit a message of all zeros. Now the decryption key is the message.

Re:I can has closed time loops?

[maxwell demon]

But the encryption key is completely random.

Re:I can has closed time loops?

[Lumpy]

The moment you create a time loop that timeline collapses. Everyone knows this.

Bonus points for creating entanglements across time lines and collapse TWO or more time lines.

Re:I can has closed time loops?

[Lumpy]

Photons can send states, you can send binary ascii this way. therefore send classical information foreward, very easy to do and then use that classical information to send backwards through the limited communication medium. If I had a single wire to only send a 1 or 0 I could send you anything.

Granted you can only send a single bit right now before the entanglement evaporates, but at some point when they can send more than a single bit of information you will have the possibility.

Re:I can has closed time loops?

[Lumpy]

keep sending 0's to the end of time... HA! I have you now moose and squirrel!

Re:I can has closed time loops?

[Anonymous Coward]

Dunno about that, but I think I could use such a device so that future me could send back the winning numbers and date of the next big lottery jackpot. Well, at least that's what I'd do provided that information could be relayed sucessfully with it.

Re:I can has closed time loops?

[Anonymous Coward]

or entangle billions of qubits and use it as bandwidth. you have one terabit of bandwidth, and once you use it up, the coms system is now worthless and you will need another com channel.

Re:I can has closed time loops?

[maxwell demon]

Photons can send states, you can send binary ascii this way. therefore send classical information foreward, very easy to do and then use that classical information to send backwards through the limited communication medium.

Sorry, but it doesn't work that way. You have to send the classical information from the sender to the receiver (because it's at the sender where it is generated). That classical information also isn't "extra", by itself it is just as random as the measurement results on the quantum system. Only if you combine both, you get transmission of information.

Makes sense enough

[erichill]

It looks like quantum teleportation meets delayed choice.

Getting so tired of this "instantaneous" BS

[quax]

Special Relativity makes quite clear that if two particles are spacelike separated when measured, that the concept of "instantaneous" is devoid of meaning.

If you have this kind of distance than you will have just one special reference frame where this is true, and infinite more where the events are arbitrarily separated in time. This is already at the core of the EPR paradox.

I.e. that you can have entanglement across time follows trivially from SR and the EPR paradox.

It's just astounding how many times the very same insight can get repackaged and sold as new.

Re:Getting so tired of this "instantaneous" BS

[avgjoe62]

It's just astounding how many times the very same insight can get repackaged and sold as new.

And that my son is why you will never work for the patent office.

Re:Getting so tired of this "instantaneous" BS

[quax]

It's a common misconception that QM as a theory of the microcosm is somehow more general and accurate than SR. Yet, the derivation of SR does not even require the constance of light speed (although that's the route that Einstein oribinally followed), but can be derived from very obvious first principles.

And this is a key difference to QM where this still hasn't been accomplished (despite the theory being such a fantastic empirical success story). Of course as far as empirical evidence goes SR also has a spotless record (which is why the CERN faster than light brewhaha was pretty much a forgone conclusion).

.

 

Re:Getting so tired of this "instantaneous" BS

[RevWaldo]

Einstein worked at the patent office. Just sayin'.

.

Re:Getting so tired of this "instantaneous" BS

[c0lo]

Special Relativity makes quite clear that if two particles are spacelike separated when measured, that the concept of "instantaneous" is devoid of meaning.

If you have this kind of distance than you will have just one special reference frame where this is true, and infinite more where the events are arbitrarily separated in time.

While the above is true, I wonder how is this relevant to the issue at hand?
I mean: who the hell mentioned something about instantaneous?

TFA:

to begin, researchers zap a special crystal with laser light a couple of times to create two entangled pairs of photons, pair 1 and 2 and pair 3 and 4.

1. First zap - they create (1,2)
2. Next zap (delta(t)>0) in the same space (delta(r)==0): they create (3,4)
Seems to me they are working in time-like conditions, aren't they?

The experiment shows that it's not strictly logical to think of entanglement as a tangible physical property, Eisenberg says. "There is no moment in time in which the two photons coexist," he says, "so you cannot say that the system is entangled at this or that moment." Yet, the phenomenon definitely exists.

My first read of TFA: the guys managed to "entangle" photons created at different times.
But then... hang on... weirder-and-weirder : they entangled photons that don't even exist in the same time.

In any case, certainly nothing to do with "instantaneous" BS, quite the contrary!

Re:Getting so tired of this "instantaneous" BS

[Lord Maud'Dib]

Whoosh!

Re:Getting so tired of this "instantaneous" BS

[Anonymous Coward]

who the hell mentioned something about instantaneous?

The summary did: "Physicists have long known that quantum mechanics allows for a subtle connection between quantum particles called entanglement, in which measuring one particle can instantly set the otherwise uncertain condition, or 'state,' of another particle—even if it's light years away."

Re:Getting so tired of this "instantaneous" BS

[jouassou]

Thanks for the link to the SR paper! It was a fascinating read :).

Re:Getting so tired of this "instantaneous" BS

[Anonymous Coward]

Special Relativity makes quite clear that ...

There is no way to end that sentence truthfully.

Re:Getting so tired of this "instantaneous" BS

[maxwell demon]

If you look at the paper closely, you'll see that it derives that under the given assumptions you get either SR (Lorentz transformation) or Newtonian space and time (Galilei transformations). The fact that he terms Galilei symmetry as degenerate Lorentz symmetry (which is mathematically true) doesn't change the fact that this argument doesn't decide between the two options. It only excludes that there's a third option.

Re:Getting so tired of this "instantaneous" BS

[jouassou]

Special Relativity makes quite clear that if two particles are spacelike separated when measured, that the concept of "instantaneous" is devoid of meaning.

From TFA:

Eisenberg emphasizes that even though in relativity, time measured differently by observers traveling at different speeds, no observer would ever see the two photons as coexisting.

So the separation was timelike, not spacelike.

Re:Getting so tired of this "instantaneous" BS

[Anonymous Coward]

I think you mixed up a lot of things. Instead of QM (classical theory) you need to refer to the most recent Standard Model. SM is a lot more spotless than Einstein's relativity. For example, when you compute Feynman's integrals for interaction of an electron with a photon you need to integrate over *all* possible speeds, including those smaller or larger than speed of light in vacuum. If you assume photons move with a constant speed only you'll get results inconsistent with experiments. [Reference: Feynman's Lectures on Physics]

Re:Getting so tired of this "instantaneous" BS

[Anonymous Coward]

Special Relativity makes quite clear that if two particles are spacelike [wikipedia.org] separated when measured, that the concept of "instantaneous" is devoid of meaning.

I thought that's the whole point of these experiments. If QM allowed some FTL-like effect yet didn't let us warp it into these kinds of counterintuitive things, it would imply that there is indeed such a concept.

Re:Getting so tired of this "instantaneous" BS

[Anonymous Coward]

MEGALOL, HAIL US GEEKS! So hard to type, must... not... laugh... Auto completion from google to: did einstein work in; result: patent office
I am glad many of my brethren and sistren don't believe all shit we can read.

Re:Getting so tired of this "instantaneous" BS

[Anonymous Coward]

From the article referred to in the original post:

"Eisenberg emphasizes that even though in relativity, time measured differently by observers traveling at different speeds, no observer would ever see the two photons as coexisting."

Re:Getting so tired of this "instantaneous" BS

[Anonymous Coward]

You're right, I know that guy, and he really never makes anything clear. I think that's why he got the nickname Special Relativity: The people he was hanging out with (which were no physicists) could make as much sense of whatever he said as they could of relativity; since he's also special in other ways, "Special Relativity" was quite right. Also, "General Relativity" was already taken, used for a (military) general who loves to say "relatively" in every second sentence.

SCNR :-)

Re:Getting so tired of this "instantaneous" BS

[quax]

Yes, I am aware of that, but the additional principle that you have to introduce is not the constance of c in all inertial reference frames, but the less strict condition that the universe doesn't allow instantaneous transfer (velocities are bounded by an upper limit). Then the fact that c has to be constant in all frames of motion follows from there.

This is essentially another new first principle - and if I have any criticism of the paper than it is that this isn't more explicitly stated.

Re:Getting so tired of this "instantaneous" BS

[quax]

Isn't it :-)

Felt the same way when I first came across it, and ever since kept wondering why SR is still taught most of the time following the initial cumbersome path - not that the latter isn't interesting as well, and certainly historically very relevant, yet this approach creates so much more clarity.

Re:Getting so tired of this "instantaneous" BS

[quax]

Regard the FLT paths as having as much physical reality as the infinite electron mass before renormalization.

ST is like making sausage, the end result is pretty good, but what goes in it can be rather stomach turning.

Re:Getting so tired of this "instantaneous" BS

[quax]

Sorry, should have made more clear that I referred to the "instant" in the /. summary.

Re:Getting so tired of this "instantaneous" BS

[quax]

Should have made clearer that I referred to the "instant" in the /. summary.

Re:Getting so tired of this "instantaneous" BS

[quax]

Ever so often not being a native English speaker catches up with me, while "constance" is a nice town, it actually isn't an English word. I guess "constancy" would do, and it'll give the none physicist more of a hint towards the meaning, than the technical word "invariance".

Re:Getting so tired of this "instantaneous" BS

[maxwell demon]

You don't need any mathematical calculations to see that the two statements

• The laws of physics don't depend on the inertial reference frame
• There's an upper limit to the possible velocities

imply that this upper limit must be the same in every reference frame, and thus anything going at that speed does so in every reference frame. That's elementary logic.

Re:Getting so tired of this "instantaneous" BS

[quax]

Fair enough.

Yes I knew it!

[can.you.feel.my.808]

Timeline really iiiis real!

Observation vs model

[Anonymous Coward]

If I had a machine, and it could only see the large circles, then all I would see is the large circles.
If I then made a model of how the large circles appear and disappear, that model would be correct, it would fit the data, it would show the probability of the circles appearing as they jump around. Those circles will jump, they'll go backwards in time, they'll do kinds of weird things.
So my equations all work, and my model of jumping circles works, ergo my model is correct?

Except it isn't, its a function of the limitations of the machine used to observe the underlying effect.

"then the Rayleigh-Jeans formula is completely correct. Never mind that it predicts that all blackbodies should be emitting radiation with infinite power"
So how fast is light really traveling in this crazy new world?

Re:Observation vs model

[umghhh]

Interesting argument. Come to think of it current physics are so complex, difficult to comprehend and counter intuitive that our ape's brains usually fail there. What this means to me is that we really are apes and have problems understanding the reality as it appears to be in its quantum and other aspects or maybe the reality is not measurable with our means at least currently. In both cases the poor soul on top of the ape brain has a problem with tools - only the tools in each case are different: one is brain the other technical methods of measuring and proving our ideas. Come to think of it nothing has changed from times Plato wrote about men chained in the cave watching the wall and shadows on it. It may be that this is more accurate theory of everything than anything else we have devised since. Utility of this theory of everything is that we should be very skeptical about things that we think are real.

Re:Observation vs model

[dargaud]

I really wonder what would happen if you kept a kid in the dark and only taught him about quantum mechanics... Would the understanding be more innate ? Or would the fact that we still need to explain it in everyday words and usual reality-based maths lead to the same interpretations ? Yeah, I'd make a terrible father.

Re:Observation vs model

[ron_ivi]

Perhaps something similar to what you suggest -- still teach the easy approximatoins -- but from the first day in high school physics start with the real solution (even if they don't understand it) and show how the stuff they'll be doing is a convenient approximation (in the same way that second grade math teaches kids rounding to the nearest 10).

That way from the beginning they'll be wired to accept that the truth is bigger than "gravity's uniform everywhere" or e=m*c*c without the momentum parts even if they use the shortcuts on tests that year.

Re:Observation vs model

[Anonymous Coward]

Of course that model would be correct. It would be correct to the limits of what can you measure, which is as good as a model can get.

Re:Observation vs model

[Anonymous Coward]

The strength of the human mind lies in the connections we can draw between things. Fundamentally, that's what we do, is draw connections. Cavemen drew a connection between the concepts of sharp and pain. Next came weapons, and then the world was doomed. Anyway, you get the picture. We're pretty smart, we can learn, but computers have us far outclassed in the raw information department.

Think of the information as puzzle pieces...the way that information fits together is almost as important as the information itself. Without fitting it together, all you have is random little factoids that aren't terribly useful by themselves. One of the things that hinders us in that is that we like to make things concrete in our minds. For example, the billiard ball model of atoms taught to children. It makes sense. They draw connections. The information get solidified. Now when you go back and say no no no that was all wrong everything is actually a bunch of strings vibrating around! They have no idea what you're talking about. Their mind will barely let them just replace the old model that worked so good. The neurological connections are already there, they take time to reform.

Doing this to your kid would make it easier for them to draw connections between things in the quantum world, but there are still a lot of even basic CONCEPTS that we don't have the foggiest idea of. We're missing pieces. We don't have enough information to be able to take a pretty good stab at it. What we're doing right now is the equivalent of trying to map the ocean floor by boating all over it and listening to the change in pitch of the motor.

Re:Observation vs model

[Anonymous Coward]

Quantum theory and relativity are also just convenient approximations that happen to work under certain useful conditions. The "Real Solution" you seek is in all probability beyond our ability to comprehend under any circumstances.

Re:Observation vs model

[ceoyoyo]

The Chewbacca defense applied to quantum mechanics. Congratulations.

Re:Observation vs model

[Anonymous Coward]

Downmod this pseudo-scientific bullshit. -1 Disagree.

Re:Observation vs model

[Anonymous Coward]

What this means to me is that we really are apes and have problems understanding the reality as it appears to be in its quantum and other aspects...

Unfortunate some more than others, and the AC that started this thread managed to get modded up for stating we can't measure something that we can actually measure...

Re:Observation vs model

[Anonymous Coward]

...yeah, that's cool, spring the linear differential equations and linear superpositions of special functions with continuous and discrete symmetries on them as soon as they reach high school. Then they'll really understand physics.

Re:Observation vs model

[ron_ivi]

You're using big words on purpose. Even little kids understand waves in pools.

Re:Observation vs model

[Anonymous Coward]

Of course kids will understand things like that... if you use analogies which are just another form of "easy approximations." The full models involve math, that if you are too far from even knowing some of the basics of, will appear completely meaningless. You can make analogies, but those are just approximations. You can discuss the boundaries and limitations of your analogies... just like they already do when teaching the approximations (assuming you pay attention to details and caveats, something students have trouble with in my experience).

Here's another theory for you

[NewtonsLaw]

Some time ago I gave some thought to the apparent anomalies and strangeness of the quantum world.

Here's what I came up with as a theory It's all about time

Comments would be welcomed from all the (real and wannabe) quantum physicists out there.

Re:Here's another theory for you

[Anonymous Coward]

I've got some interesting theories along similar lines too... but I suspect I'd have to do some math and make some interesting predictions before anyone paid attention to me. I haven't looked past the page you linked to yet but have you expanded on your idea in this way yet?

I don't yet want to share my idea as it's still just an idea I'm toying with.. and I'd like to develop it a bit further so that I can hope to claim some authorship to it if it has any merits.... but I suspect it might just remain an idea... but I'll write it down in case someone else does the legwork so at least I can say with some personal understanding that "I thought of that"!

Re:Here's another theory for you

[ledow]

The problem is that to be accepted in an area of science that's basically nothing more than a consequence of the maths, you have to show the maths that generate the results you expect.

I'm a mathematician. I don't claim to understand 1% of 1% of quantum mechanics at all. But it comes from a mathematical model that happens to have real-world consequences that are weird and wonderful. When we then tested for those consequences, we found out that they exist in nature. Which, to a scientist mind, kind of hints that the maths must have been at least somewhat correct (or at least on the right lines).

I have my own understanding and theories, but I would also have to state, quite clearly, that quantum physics isn't really "physics". This isn't Newton seeing an apple fall and realising there's a force at play. This is someone (probably THE most famous genius) sitting down for decades with almost unsolvable equations that make absolutely no sense until they realise that it works if you have 11 dimensions, or if space and time are two different elements of the same thing, etc. And that was back in the 1900's when quite a lot of physics and maths we enjoy now didn't even exist.

Then you go out and measure in real life and you find that, actually, it turns out that your theory fits what happens in the world, not the other way around.

As such, I don't for a second think that I can just posit a hypothesis (theory is a slightly stronger word in any science) and have any concept of if I'm talking gibberish or not. The maths of quantum mechanics is horrendous and complicated and quantum theorists spend more time in front of the blackboard than they do the LHC.

If you wish to contribute, even if you don't intend to be taken seriously, it's only proper to get yourself a decent grounding in not just "hey, there's something smaller than an electron and weird stuff starts to happen at that scale, I bet I can guess what else happens", but in WHY that's so and HOW we got to that point. And in anything quantum, that means understanding the maths behind it.

As someone with a degree in maths, I tell you now, you're going to need a decent grounding in quite a lot of basic physics and huge amounts of maths and that "real world intuition" will basically be next-to-useless until the very end. That's not to mention the level of things like calculus and linear algebra you'd need to even get close to learning how we got to all of the old "wrong" models, let alone the newer ones.

This doesn't mean that wild ideas and theories have no merit, it's just that you're theorising about something that you probably don't understand the basics of. I know I don't. And I *can* read the mathematics and, given enough time, understand it.

It just comes across to any mathematician or physicist as someone who is looking at a car for the first time and saying "You know, I bet if you made the whole thing ten times bigger, it would go even faster" or "If it goes that fast with four wheels, imagine what it'll do with 10!".

In a way it reminds me of the Moon conspiracy theorists. They can come up with a million weird and wonderful things that intuition says "must be wrong". But it turns out that a few simple tests or bits of maths show them to all be nonsense. "The shadows are wrong" - fine, go out into the street on a sunny day and try hard to replicate them. If someone can replicate something that's "wrong" in the space of ten minutes, then maybe you are reading far too much into the image, or commenting on something you just don't understand.

https://en.wikipedia.org/wiki/Introduction_to_quantum_mechanics

Seriously, just on that page there are some 16 equations, and that's not even a millionth of what you need to understand where those equations come from.

Honestly, I DON'T understand quantum mechanics at all. I believe it, because it's accepted as the best self-consistent theory we have that has made verif

Re:Here's another theory for you

[Anonymous Coward]

http://www.timecube.com/

Re:Here's another theory for you

[bbasgen]

How eloquent and poignant. Well stated.

Re:Here's another theory for you

[Anonymous Coward]

I have my own understanding and theories, but I would also have to state, quite clearly, that quantum physics isn't really "physics". This isn't Newton seeing an apple fall and realising there's a force at play. This is someone (probably THE most famous genius) sitting down for decades with almost unsolvable equations that make absolutely no sense until they realise that it works if you have 11 dimensions, or if space and time are two different elements of the same thing, etc.

I think you're confusing quantum mechanics with string theory (apart from the genius part; but then, while Einstein — the only one qualifying for the title "the most famous genius" — made important contributions to quantum mechanics, the actual modern theory is due to Heisenberg and Schrödinger; I don't have an idea who invented string theory, but again I'm pretty sure Einstein didn't).

Quantum mechanics was also invented to solve very concrete physical problems. It began with Planck questioning why bodies don't radiate infinitely much energy, it continued with Einstein explaining the behaviour of electrons emitted from a metal when you shine light on it, and with Bohr explaining why atoms are stable, despite electrodynamics saying they can't be. Then people though about the consequences, and yes, there was also speculation involved, but not very wild speculation. For example, after it was established that light could have both particle behaviour and wave behaviour, de Broglie asked whether it couldn't be the case also for things we know as particles. He worked out what this would mean, and the experiments indeed found it. And ultimately Heisenberg and Schrödinger formulated a coherent theory.

If that's not physics, then what is?

Re:Here's another theory for you

[hAckz0r]

Quotes on Imagination, Intuition,Curiosity by Albert Einstein
"Imagination is more important than knowledge."
"The only real valuable thing is intuition."
"I have no special talent. I am only passionately curious."
"The important thing is not to stop questioning. Curiosity has its own reason for existing"
"All these primary impulses, not easily described in words, are the springs of man’s actions."
"I am enough of an artist to draw freely upon my imagination."
"Knowledge of what is does not open the door directly to what should be."
"Logic will get you from A to B. Imagination will take you everywhere."
"The gift of fantasy has meant more to me than my talent for absorbing positive knowledge."
"To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science."

http://ownquotes.com/blog/top-albert-einstein-quotes-famous-albert-einstein-quotations/

If Einstein valued imagination so highly then do would mathematicians completely discount it so quickly? Yes, Mathematics is a very valuable tool, once you have a formula. You can then use that formula in many interesting ways to show the relationships between things. You can calculate the state of objects given perfect knowledge of the beginning states, for very simple systems. Unfortunately that formula needs to be developed through a creative process and only then it can be demonstrated through experiment that it actually models reality. Mathematics alone unfortunately can also be used to show impossible things. Things that can never happen in the real world. That is why we test things. Only imagination, logic, and thoughtful experiment can set the bounds on where Mathematics applies and where it does not.

I'll make you a deal. I'll hand you a paper describing a physical framework by which first principals of physics, Thermodynamics, and the effects of Special Relativity can together physically explain any paradox (including TFA above, QM, SR, GR, Cosmological) that you can throw at me, and you can then write the formula that describes "The Universe" and collect the Nobel Prize. No, I'm not kidding, and yes, I'll let you keep every penny of it.

The problem is that the formula itself will be self referential (that is actually a requirement for any complete Unification theory, and I will debate you on this), and any computational model built with that formula will be guaranteed to be computationally intractable in both time and space requirements. Even if you had perfect knowledge of the state of every particle in the Universe there would be no exact answers coming out of it. As a mathematician, how will you then make use of a formula like that? You will have to look at the formula and make cognitive predictions based on the relationships that it suggests, and then test those assumptions in real world experiments.You will thus be generalizing that formula because you won't be able to calculate an exact answer to anything. Is your logic now more mathematical or philosophical? Einstein would call it intuition.

Why would I make that offer? Because I can't publish my theory without the math, exactly because of the "math is everything" attitude amongst the physicists and engineers I work with. I have spent three years writing and trying to get a peer review within my University physics lab and can't even get anyone to take me seriously enough to read the paper and try to understand why it works. I have even offered to pay significant money to anyone who can find any self inconsistency, falsifiable evidence, or any kind evidence to falsify even a part of the framework. Yes, I actually offered to PAY someone to falsify my own theory. As long as there is even a 1% chance the theory it correct I need to keep working on it, and quite frankly I want my life back. But without the math its clearly going nowhere any time soon despite it having testable but non-mathematically derived predictions.

BTW - The fine article is from last year. Why its it being posted on Slashdot now?

Re:Here's another theory for you

[hawkfish]

Some related ideas:

Doubly Special Relativity.
Henry Stapp on Whitehead's Quantum Ontology

Re:Here's another theory for you

[Anonymous Coward]

Read Feynman's "Q.E.D."

It gives a very simple explanation of quantum mechanics, and why you don't need all the maths to understand it (as much as anyone does) - the math is "just" a way to be able to sometimes be able to make predictions based on QM in a reasonable amount of time. That's a paraphrase of what Feynman writes in the book - lacking the prerequisite Nobel prize in physics for work on quantum mechanics, I do not feel qualified to say that myself, but the book is clearly interesting and helped me get a better feel for QM, as far as I have one.

Re:Here's another theory for you

[Anonymous Coward]

The problem is that the formula itself will be self referential (that is actually a requirement for any complete Unification theory, and I will debate you on this), and any computational model built with that formula will be guaranteed to be computationally intractable in both time and space requirements. Even if you had perfect knowledge of the state of every particle in the Universe there would be no exact answers coming out of it. As a mathematician, how will you then make use of a formula like that? You will have to look at the formula and make cognitive predictions based on the relationships that it suggests, and then test those assumptions in real world experiments.You will thus be generalizing that formula because you won't be able to calculate an exact answer to anything.

The problem is seeing stuff like this. Either you are having great difficulty at conveying your ideas, or your ideas are nonsensical. A large part of the reason math gets used so much in physics, is it can concisely convey very precise meaning. Such things can still be conveyed with words, but it takes a lot of care and effort. Instead, my coworkers and myself at the physics department I work at, get a lot of cold emails from people that have trouble conveying things, because they never learned terminology or defiantly refuse to use any standard terminology. When you have to spend all of your time trying to just understand what they are trying to say, you are not left with much time to spend on the actual idea. And you are lucky if you get that far, as looking at some things like this, after wondering if someone simply didn't bother to define their nonstandard terms, or if they don't understand what those terms mean, or if it is just word salad, you move on to things judged to be more productive without looking back.

Yes, it is an unfortunate barrier to entry to develop one's communication skills and repertoire to the necessary level. It is also a bit of a barrier to become aware of all the relevant previously performed experiments, but it shouldn't be surprising if something that agrees with one experiment gets disregarded because it ignores a dozen others.

Re:Here's another theory for you

[prgrmr]

planck time http://en.wikipedia.org/wiki/Planck_time would suggest that the answer to your question is "no"

Re:Here's another theory for you

[Anonymous Coward]

Time is a consequence of finite speed of light. That's all.

Also in QM,
delta(energy) ~= h-bar / time

so you can say,
delta E * delta t <= h-bar

Re:Here's another theory for you

[Agent0013]

I do think you have a very good point about putting out wild guesses to what is happening at the quantum level without an understanding of the math being pretty useless. It seems that quantum mechanics is pretty non-intuitive and trying to think about what is happening does not work. You just have to look at the math and equations and see what it does. Even QM physicists don't "understand" it. But on the other hand, perhaps we don't understand it because we are looking at in the wrong way. It could be that learning the math to do QM correctly will give you too many incorrect paradigms that will keep you locked into the current way of thinking and you won't come up with the paradigm shift needed to make a breakthrough. I saw someone post an interesting way to think about the speed of light and how it is constant no matter what speed you are traveling. Think about the horizon, it moves away from you at the same speed no matter how fast you move towards it. Instead of thinking about time changing with your speed, you can imagine a new way of thinking about it that is less intuitive, but still gets to the heart of the matter at another way. I think QM or physics in general will need a paradigm shift before things like these experiments make sense. Once we think about what is happening with entanglement in a different way we may start understanding how that affects the macro world and may start to understand time and gravity better.

The summary makes a bigger deal of this than it is

[Y.A.A.P.]

When you read the article, this isn't actually too controversial. All that's being done is changing the timing of of when the measurements are taken and when the intermediate photons become entangled. It's really just using the entanglement process to spread out the time over which the quantum state data is transmitted. You basically have a quantum data historical record.

I can certainly see this opening up useful new capabilities in quantum computing and measurement of quantum phenomena, but it doesn't change our understanding of quantum events and how they interact with our "everyday notions of space and time.".

Slower than the speed of light

[XNormal]

Superposition, wave function collapse and other quantum effects are supposed to govern everything. But I don't seem to recall any such weird experiments that do not involve any particle traveling slower than the speed of light.

Are there any such demonstrations that involve only interactions between particles having nonzero rest mass?

Re:Slower than the speed of light

[wonkey_monkey]

The double-slit experiment can be done with electrons and atoms.

Re:Slower than the speed of light

[maxwell demon]

The double-slit experiment can be done with electrons and atoms.

And with C60 molecules.

Also, ions have been entangled.

Re:Slower than the speed of light

[wonkey_monkey]

I heard or read something about a macroscopic object being put into a quantum state of vibrating/not vibrating. Not sure if they managed it, or just thought they could.

Re:Slower than the speed of light

[maxwell demon]

There are several proposals (and calculations) about entangling (microscopic, but still large compared to typical quantum systems) cantilevers, but I'm currently not aware of an experiment which already did this (and didn't find any with a quick Google Scholar search).

Re:Slower than the speed of light

[Anonymous Coward]

I don't know of any macroscopic entanglements, but about three years ago macroscopic cantilever was put into superposition: Paper in Nature.

No Science, No Porn

[ikaruga]

Without quantum physics the cameras, fast CPU, GPUs and high speed communications that help me cope with my solitude at night wouldn't exist. Count me out brah.

There's nothing more slippery than an Israeli.

[Anonymous Coward]

No doubt they will try to find a way to use this to further extort money and military aid from their "friends."

42?

[future assassin]

????

Star Trek era looming

[multatuli]

Yes! Subspace communications!

Before and after

[Taco Cowboy]

Question: Within the context of quantum mechanic, what is the behavior of TIME ?

What I read from TFA is that they observe a certain particle at the before time frame, and then compare it with another particle at the after time frame, and found some "entanglement"

What if the experiment is carried out on the reverse --- someone checking out a particle at the after time frame and then, some others compare it with another particle at the before time frame and see if they entangle or not

I do understand that experiment that I have just described can't not happen with the limited technology that we have, for the after can not happen _before_ the before

That's why I am falling back to my original question --- what is the behavior of TIME within the context of quantum mechanic ?

Can an "after" happen _before_ a "before" ?

Re:Before and after

[Anonymous Coward]

No.

Re:Before and after

[Skapare]

But what if someone later decides to NOT do the after step, even though the before step has already happened and its answer is in the sealed envelope?

Re:Before and after

[Lumpy]

Actually we know very VERY little about the Time dimension. Only recently did we prove frame dragging even existed. we still have not proved other distortions of time NOR if the rules of time change for quantium level.

Re:Before and after

[fritsd]

Question: Within the context of quantum mechanic, what is the behavior of TIME ?

AFAIK, it's simplest to describe things with the time-independent Schrödinger equation: H Psi = E Psi. This is close enough for most stable molecular states in chemistry. However, if you're talking about state transitions or spectroscopy or (as in this case) entanglement, you have no choice but to use the time-dependent Schrödinger equation: i h-bar d Psi / d t = H Psi, which is MUCH more difficult.
That H is not a variable but any suitable Hamiltonian operator, which usually has second-derivative goodness AND a complicated Psi-dependent potential energy term. BTW whoever made that Wikipedia page on the Hamiltonian: thank you, it's very clearly written!

AFAIK, entropy is not described at the quantum level, so Ilya Prigogine's "arrow of time" doesn't really exist, and you can just reverse the behaviour of time by putting a minus sign in front of it and see what happens. In Physics, I read this can be done by drawing a Feynman diagram and turning it upside-down.

I hope this helped answer your question...

N.B. if any "real" quantum chemist or quantum physicist reads this and cringes, please mod this down; it's better to give no information than false information!

Re: Before and after

[Anonymous Coward]

I think so...
Http://www.nature.com/physical/journal/v8/n6/full/nphys2294.html

Re:Before and after

[RabidReindeer]

But what if someone later decides to NOT do the after step, even though the before step has already happened and its answer is in the sealed envelope?

That's when you let the cat out of the box!

Re:Before and after

[Anonymous Coward]

"Question: Within the context of quantum mechanic, what is the behavior of TIME ?"

Same as always, they keep trying to get you to subscribe

Re:Before and after

[Will.Woodhull]

QM is not so hard, once a person realizes that quantum mechanics is all about semantics and has nothing to do with physics.

For instance, the difficulty in understanding this quantum entanglement of photons separated by time collapses into meaninglessness as soon as one accepts that "time" is an attribute of "observation" and has nothing to do with reality (whatever that might be).

As soon as you get past the desire to structure your memories in a simplistic linear fashion, you will realize that was zen, this is tao.

[Did author of this post intend to convey any kind of meaning to the reader? That doesn't matter--- what matters is whether the reader extracts any kind of meaning from the words of the author. Confused? Good. To be other than confused in this universe is to deny the reality of what you observe.]

Re:Before and after

[Will.Woodhull]

Ah! The old 'feline is out of the sacculus' trick.

The answer to GP post is obvious: if the after is never done, then the envelope is never opened. At the end of time there will be a massive pile up of all the photons that have never been collapsed into one state or another, which probably will have something to do with the post universe having an excess of matter over antimatter. Or something.

[If this seems to make any kind of sense, then perhaps you should be studying on how to climb the mountain rather than wasting your time rubbing heads with slashdotters. Amusing though that can be.]

Re:Before and after

[Xaedalus]

Shit, I think I understood that. I better go buy myself some hiking shoes... I need to stare out into vast distances now...

Re:Before and after

[SoftwareArtist]

Can an "after" happen _before_ a "before" ?

As far as we can tell, yes. This is known as retrocausality, and experiments have been done that it's at least plausible to interpret as having observed it.

This is a very thorny subject because we have so many biases about how the universe "ought to" be, and it's hard to even talk about the subject, much less interpret an experiment, without bringing in all those biases. But I'll describe the interpretation that I find the cleanest, simplest, and most appealing. Other people have other views.

First, you need to let go of your presentist way of thinking about time ("only this moment exists") and accept an eternalist, block-universe viewpoint: space-time is a continuum that all exists "at once", and what you call "the present" is merely an arbitrary slice through it. The arrow of time is likewise arbitrary: the future affects the past in precisely the same way that the past affects the future, and information propagates in both directions according to exactly the same equations.

Once you accept that, all the strange features of quantum mechanics disappear. Entanglement is an illusion created by ignoring the information flowing in one direction. The collapse of the wavefunction isn't a change to the thing you're measuring, just a change in what you know about it. The uncertainty principle is just a limit on how much you can learn by doing an experiment.

If you want to learn more about this subject, this article is a good place to start.

Re:Before and after

[martijn hoekstra]

The longer I think about it, the likelier I find it that time is in fact an emerging statistical behaviour equal to the entropy arrow of time. That would allow for local statistical reversal of time, and balances out any difficulties of cause and effect, where the difference between cause and effect is defined as effect having a higher entropy than cause. I have a nagging feeling a lot of things may be involved in this (even P ?= NP can maybe seen as a form of this, where an unsolved problem describes a system with the same energy as a solved problem, but the unsolved problem has higher entropy). Unfortunately, I lack the rigor to properly work something out. Feel free to downvote based on crackpottery.

Re:Before and after

[SoftwareArtist]

This is basically correct. Most people state the 2nd law of thermodynamics backwards. There isn't any fundamental law of nature that causes entropy to increase with time. Rather, we define "forward in time" to mean, "the direction of increasing entropy." In our local region of spacetime, that translates to, "away from the big bang."

What's surprising is how few physicists really understand this. None of my textbooks ever described it that way. Yet Boltzmann understood this perfectly well in the 19th century, and described the situation very clearly.

If you're interested in learning more, a good book on the subject is From Eternity to Here by Sean Carrol. The author has also given a couple of TED talks on the subject.

Re:Before and after

[Anonymous Coward]

That was a most eloquent misinterpretation of Boltzman I've seen in a while. Maybe if the universe was made entirely of infinite micro-universes, AND consisted ONLY of ideal gases of infinite dilution we could get your idea of entropy and time to coincide with your mathematical models.

Re:Before and after

[spiralx]

Julian Barbour's The End of Time is a good read by someone who's done a lot of work on this issue.

How can they tell if 1 and 4 do not coexist?

[master_p]

According to the article, particles 1 and 4 do not coexist. Therefore, one must be destroyed before the other is created.

But if 1 is destroyed before 4 is created, then the entanglement of 1 and 2 is broken before 3 and 4 are created (because 3 and 4 are created together, and then 2 and 3 are entangled).

So, by the time 2 and 3 are entangled, 1 does not exist, because 3 already exists and is entangled with 4.

The question that arises is then how do they know that 1 and 4 are entangled?

It could simply be that 1 and 4 show the same state when measured, because 1 and 2 were entangled, then 3 and 4, then 2 and 3. Which means that whatever entanglement existed between 1 and 2 will exist between 1 and 3 and 1 and 4, even if 1 does not exist.

That does not mean particles are entangled across time. It may mean that entaglement is simply peristent and transmiitable.

Most probably there is a misunderstanding somewhere between the announcement and the article, so please anyone that knows more, elaborate.

Re:How can they tell if 1 and 4 do not coexist?

[Anonymous Coward]

"That does not mean particles are entangled across time. It may mean that entaglement is simply peristent and transmiitable."

so... there is life after death?

only semi tounge in cheek ;-)

Re:How can they tell if 1 and 4 do not coexist?

[Splab]

Most probably there is a misunderstanding somewhere between the announcement and the article, so please anyone that knows more, elaborate

Magic, it's done by magic.

Re:How can they tell if 1 and 4 do not coexist?

[Andyupnorth]

Nice summary. Very understandable and logical. Thanks!

No surprise, due to different reference frames.

[master_p]

Entanglement exists outside of reference frames. So, it exists across time.

This means that there is a super reference frame which includes all possible frames and allows for things to persist (and perhaps move) across time.

Spooky action at a distance....

[rts008]

Now I understand Einstein's wild hairdo....

I think the rabbit hole may be a wormhole without the other end!

*head asplodes!*

Trying to find a way home.

[senorpoco]

They could only be connected to other particles that existed in their lifetime and then they would have to perform a good deed before being able to connect to a different particle. Oh boy

There are FOUR states

[Anonymous Coward]

Solid, gas, plasma, liquid and superfluid... there are FIVE states:

Solid, gas, plasma, liquid, superfluid and Strange matter...: there are SIX states:

This can go on a while, there are a LOT of extra states besides the four fundamental ones.

Basically the rule is: there are only four fundamental states of matter except for a whole lot of weird ones but just pretend they don't exist, we just need them for the universe to work.

Re:There are FOUR states

[Pseudonym]

Bugger, I'll come in again...

You're right. The four states of matter should be more correctly called the four familiar states of matter, because everything that you can see in your everyday life is in one of those states.

However, the concept of a "state of matter" doesn't actually exist in nature. They're just words we apply to configurations that matter can find itself in, to help organise our thinking.

Since this article will (hopefully) attrackt peopl

[Kartu]

Since this article will (hopefully) attrackt people who are into QM, let me ask 2 questions that I'm struggling with for a long time (and thank you in advance for bothering to answer):

1) What is a "measurement"? How big should an object be to actually "collapse" the wave function?
2) The FTL (well, actually instant) "spooky action in the distance". If particles really can interact like that, how come we can't use it to transmit information? And if we can't, why "hidden variables" assumption that particles had certain values upfront is disregarded?

Real Programmers

[Anonymous Coward]

Real Programmers can write spaghetti code in any language. In fact I have worked with just such a twat, and he was indeed convinced that he was a Real Programmer. After he left I rewrote his disgusting snarl of a comms service using queues and classic asynch programming completion handlers, and it was a tenth of the size and almost 200 times faster on the same hardware.

I cannot help but speculate that God might also be an egotistical wanker and the universe in desperate need of a rewrite. Certainly the scriptures support this view.

mmm, I wonder if

[houbou]

it is possible that life is a mixture of quantum state and this dimension. Thus the reason for being able to think and have a feeling of self?

probably should build the lab on Phobos

[Anonymous Coward]

So, like, if they can entangle a photon with another photon that doesn't exist at the same time, it should be a simple matter of engineering to entangle a photon with another photon that doesn't exist, right?

Re:The summary makes a bigger deal of this than it

[bill_mcgonigle]

Ah, thanks for this. So, it sounds like it's probably possible to preserve a quantum state over time, which is good for us in the real world where things tend to break and get lost.

This must've been what Scotty did when he put the pattern buffer into its diagnostic cycle. Except, poor Franklin, in the real world things break and get lost.

Same time?

[Anonymous Coward]

Same time, in physics?

t != t'

Awesome

[Jesrad]

Multiverses can interact !

less and more

[Thud457]

Is less more more than more less ?

who cares?!

[Anonymous Coward]

it's all about money. not time, not space. just a fantasy believe called money.
physics stopped being for the public knowledge after WW2 and finding some
nasty stuff that borders on the fantasy / harry potter realm ...and .. the first helicopter
in some nazi bunker etc...
it's very convenient to have found a fixed "un-moveable" point in the universe where upon
one might rest his lever and move the universe, called "constant-light-speed" because
pretty much anything mundane in daily life is based on these "photons" ... in other words
it's a fantastic hack to pull the horse-shades over the eyes of people willing to listen,
because EVERYTHING we interact with in daily life is by LOOKING, thus by registering photons.

here's a hint: YOU exist. everything YOU DO has an influence. now go and be smart
(a so called first mover) and see if you can make nature follow ...
oh and i understand if you don't want to explain how you did : P

At The "Same Time"?

[Tyler Durden]

Sorry, I don't have the time to RTFA, but it seems strange to talk about entangled photons that don't exist at the "same time" when SR say simultaneity is relative. While they might not exist at the same time in one reference frame, you'd think there's bound to be one in which they do.

Re:At The "Same Time"?

[Tyler Durden]

My bad. Helps to read.

And even though photons 1 and 4 never coexist, the measurements show that their polarizations still end up entangled. Eisenberg emphasizes that even though in relativity, time measured differently by observers traveling at different speeds, no observer would ever see the two photons as coexisting.

Time and Photons don't mix

[Anonymous Coward]

Time is not a meaningful dimension in a photon's reference frame. Because in a photons RF time appears stopped. Therefore a photon interacts with any photon ever created in the universe. Duuh!

+5? This is flat out wrong

[Anonymous Coward]

I think this is the same AC that has been posting this on nearly every quantum mechanics related topic of Slashdot, and it is completely wrong. Whoever posts this keeps assuming the only way photons can be detected is by discrete raising and lowering of electrons in an atom, which is flat out false. There are other detection methods, such as scattering methods, which can detect things in a continuum and not in a discrete sense. If you don't have the background of even an intro level physics class, your physics theories are probably going to quickly contradict reality. In some cases, to almost a laughably bad level.

Not that strange

[drrilll]

Time is relative too. If you and I are in the same room we appear to be in the same "time" the same way that the Earth appears to be flat, because the difference is too small to notice. But the "time" of you or I or any given particle is as distinct as its space. Of course, the ramifications are not quite that simple (because of time's arrow, etc), but it seems well within accepted theories.

At least, that is my take. I am a physics hobbyist, so it is entirely possible that I have completely misinterpreted the underlying theory. If I did, uh, well, sorry, and best of luck with all that photon stuff!

My dream is coming true

[Anonymous Coward]

This is just one step closer to the dream I had about a fusion generator that relied on quantum effects across time.

Slashdotter vs. Science

[Anonymous Coward]

If a slashdotter only knew of how to make measurements that see larger circles, then all they would think scientists could measure is larger circles.
If the slashdotter than made a model of how scientists work, they would assume all of the science is based on large circles, how the appear and disappear, jump around, etc..
If the slashdotter never actually bothers to learn more about the field they are criticizing, then it would appear their model is correct, and that scientists must surely be stupid for not acknowledging it.

Except the slashdotter's model isn't correct, it is instead a function of the ignorance they have of basic physics.

"If all you can see (and measure) is a photons promotion and demotion of electrons"

But in this crazy, real world, that is not all we can see and measure... and we've been doing otherwise for nearly 100 years.

The original AC get +5 Insightful by drawing a conclusion that ignores some pretty basic things that have been around for a long time. It is on par with someone to claim that people shouldn't apply Moore's law about transistor count to computers, because computers only use electromechanical relays...

Not that surprising

[Anonymous Coward]

At the speed of light, time is irrelevant. Everything is happening at the same time. It's pure energy in different states - each state being relative to a time period in our reality as we understand it, but not in the real reality - the light.

Re:Not that surprising

[Anonymous Coward]

like with numbers

Re:The summary makes a bigger deal of this than it

[onebeaumond]

Yes, have to agree. Couldn't a valid observation of this experiment be that "the entangled property of photon 2 does not change with time"? This would explain things without having to violate "everyday notions of space and time". At least, no more so than usual.

Not Spooky at all

[n2hightech]

This spooky action at a distance thing is hogwash. All the data points to random persistent polarization. Once a pair of entangled photons are produced they each have a definite polarization that persists over time and space unless you do something to it. That is Newtonian. A body in motion remains in motion until acted upon by an external force. A photon polarized at an orientation remains in that orientation until acted upon by an external force that changes the orientation. Creating a new photon polarized the same as an existing photon is not spooky.Hard to do and maybe very useful but not spooky. The Bell experiment / theory has been badly abused and interpreted in an odd way. Its results show conclusively that once photons are created in an entangled way the polarization of the individual photons remains aligned between those two photons. It proves that the unassigned BS is BS. The polarization is a definite fixed value and stays that way until you do something to the photon to change it. Saying its polarization is all orientations until the wave function collapses is not accurate. One photon has one polarization. We do not know what it is until we measure it. Because we do not know what it is does not mean its polarization is undefined. Undefined Unknown. The population of photons have a random range of polarization. But each entangled pair have a matched polarization.

Re:Not Spooky at all

[Anonymous Coward]

All the data points to random persistent polarization. Once a pair of entangled photons are produced they each have a definite polarization that persists over time and space unless you do something to it.

Suppose you had a system that emits two photons with polarizations 90 degrees apart (i.e. one vertical, one horizontal). Now if they were not entangled and there was just a vertical and a horizontal photon heading out, and you sent both through a filter at 45 degrees, you would independently have a 50-50 chance at each end to see a photon coming out of the filter. So in total, there would be a 25% chance of seeing a photon at both ends, 25% chance of seeing no photons at either end, and two different ways at 25% each of seeing one photon at one end and no photon at the other end. However, if you entangle the photons, you will always get exactly one photon total after the filters, with a 50-50 chance of it coming out a particular end. You cannot get those probabilities by assuming the photons have a persistent polarization before going through the 45 degree filter.

Re:Since this article will (hopefully) attrackt pe

[Anonymous Coward]

1) What is a "measurement"? How big should an object be to actually "collapse" the wave function?

Any interaction with the world outside the system being considered will affect or collapse the wave function. This can be the result of useful measurement, or just by accident resulting in noise.

If particles really can interact like that, how come we can't use it to transmit information?

Short answer: When you break the entanglement, you can't control which state the opposite end gets, so they still see the same mix of states they would have seen before you broke the entanglement. Even when doing teleportation, the copy at the destination is scrambled, and they would get something random unless you tell them the result of a measurement made at the source that tells them how to unscramble it. You don't see anything happen when someone breaks or does something to the other end of the entangled pair until they tell you what you they did or saw, then you see a coincidence or correlation between the ends. But without knowing what the other end did, you get the same random mix of outputs that conveys no information.

And if we can't, why "hidden variables" assumption that particles had certain values upfront is disregarded?

The simplest examples frequently used make it look like two people drew marbles from a bag that starts with a black and white marble, and then walked away and see that they end up with opposite colored marbles. This is sort of how the simplest entanglement looks, but it makes it look like something classical when actual quantum entanglement in slightly more complicated situation will do things no classical system can.

One example used is to consider the spin of a particle, an axis that has some direction. There are ways of making sure it is either up or down, and entanglement processes that produce two particles such that they point in opposite directions. If you only look to see if you get the one pointed up or the one pointed down, it looks like the case of pulling marbles out of a bag. But you can go further, and ask if it is pointed left or right. If the spin is pointed up or down, and you measure which way side ways it is pointing, you get left randomly half the time, and right randomly half the time, since it was really pointed left or right to start with. Now you do this to the entangled pair. If it was true that one was up from the start, and the other is down from the start, you would have a 50-50 chance of getting left or right for each particle, meaning you have a chance of seeing two lefts or two rights. But with quantum entanglement, you will see only a left and a right half the time, and a right and a left the other half, never two lefts or two rights. And it is still has a 50-50 random aspect to it, so both ends it will look like random noise until they talk to the other end.

Send messages back through time?

[Anonymous Coward]

doesn't this mean it's possible to send messages back and forth through time? people in the year 2013 talking to people in the year 3013?

Doesn't this mean...

[countach]

that we can send information back in time, like tomorrow's lottery numbers? The outcome of a race? That we were involved in an accident tommorow, and now we can avoid it? Once that is possible, doesn't life as we know it collapse?

Has anyone tested that?

[Anonymous Coward]

The whole 'quantum entanglement works even when the particles are light-years apart' thing... I'm pretty sure that hasn't been tested in a lab.

Or if it has, that must be a pretty big lab.

Do we know it would work? No. We can dream it, think it, believe it certainly, but know it? Not in this lifetime.

Do photons know we are talking about them??

[TheRealHocusLocus]

The word is made of quips and quibbles, cubistic holo-bits and hobbits of brick-a-brac espoused to melanges of malarkey. A fright-night of fundamental foolery gathers in search of data to complete a theory which states that it, the theory itself, does not exist. Therefore there is no theory, which leaves itself unproven thus possible.

These two photons walked into a bar. "We're entangled!" they slurred repeatedly, making the patrons around them more annoyed than shocked. The bartender turned to face them and the bar dissolved into a branching fog of multi-way almost-events because their entanglement could not exist to be observed and a bartender's eyeball is the lighthouse of the soul. Ask anyone.

Time to pull the chain and flush your mind.

Color TV

[Anonymous Coward]

Color TV has been around for about 60 years. Airplanes been around for about 100 years. People have been around in recorded history for about ten thousand years. Cells used to be thought of as simple organisms, but electron microscopy has revealed the inner workings of cells as complex. DNA has recently been decoded. Nanotechnology is very recent. Television has 10,000 channels (ATT U-Verse has at 9999 numbered channels, though less than 10% are used). Everyone walks around with a camera in their phone (phones outnumber toilets in the world!). Cruiseships are big as small cities. Los Angeles is a big city.

Matter, energy, space and time - I think we have a ways to go in understanding all that stuff. Can matter exist in two places at once, at two different times, and for that matter in different states? Quantum physics seems to think so.