Quantum Theory Experiment Said to Prove "Spooky" Interactions (economist.com)

universe520 writes: Albert Einstein was troubled by how two particles can communicate with each other even if they are on opposite sides of the galaxy. Today researchers in the Netherlands have closed the final two loopholes in how quantum entanglement works. The Times reports: "The new experiment, conducted by a group led by Ronald Hanson, a physicist at the Dutch university’s Kavli Institute of Nanoscience, and joined by scientists from Spain and England, is the strongest evidence yet to support the most fundamental claims of the theory of quantum mechanics about the existence of an odd world formed by a fabric of subatomic particles, where matter does not take form until it is observed and time runs backward as well as forward."

Comments

"and time runs backward as well as forward."

[Arkh89]

"and time runs backward as well as forward."

It had to be published today, right Doc?

Re:"and time runs backward as well as forward."

[Stormbringer]

Nah, it's ten days early.

Re:"and time runs backward as well as forward."

[Anonymous Coward]

Remember that these are the same people arguing against the Universe having a creator....

Re:"and time runs backward as well as forward."

[jc42]

Remember that these are the same people arguing against the Universe having a creator....

Nah; they've just found that the "creator" worked at what we consider the (heat) death of the universe, and the creation has run backward since then. We don't remember something until the universe reaches the event we're trying to remember, and then it sends a description of the event forward along your time line. This transmission has a significant error rate, of course.

Does that clear it all up? If not, wait a bit, and someone farther back will send a more detailed explanation. Of course, since it'll be traveling longer, there'll be more dropped bits, so we may not be able to make as much sense of it.

Re:"and time runs backward as well as forward."

[Ramze]

No. They aren't "arguing against" the Universe having a creator. They simply have no evidence FOR one, so they dismiss the idea.

If you have scientific evidence, then please present it. If not, then it's not science and science has nothing to say about it.

Re:"and time runs backward as well as forward."

[Anonymous Coward]

Technically, the facts of the matter are actually the idea there is no evidence of a necessity of a sentient Creator and, consequently, a model without a sentient Creator is simpler than one with.

Re:"and time runs backward as well as forward."

[Anonymous Coward]

The creator issue is very similar to the life on Mars issue.

There is an international agreement to not contaminate Mars until we are sure there is no life there.
The problem is that there always is somewhere you haven't looked.
Did you turn every rock on Mars? Well, perhaps you didn't dig deep enough? What if it moves, perhaps all rocks needs to be turned at the same time or perhaps you just don't know what life looks like?
Proving that something doesn't exist is very hard. Proving that something exists on the other hand isn't harder than finding it and showing it.

For proving that something doesn't exist it would be very practical if we could agree on what "good enough" means.

Re:"and time runs backward as well as forward."

[Anonymous Coward]

Here you go. Peer-reviewed.

Now go ahead and equivocate "science" or "evidence" to the degree necessary to comply with your pre-existing bias.

Re:"and time runs backward as well as forward."

[HairyNevus]

From your link:

Interpretation

We do not know why so few cardiac patients report NDE after CPR, although age plays a part. With a purely physiological explanation such as cerebral anoxia for the experience, most patients who have been clinically dead should report one.

How does that refute GP or even show anything of substantial value to the debate of whether or not there's scientific evidence for a creator? Go ahead, twist the findings of that study to say what you want them to. Do it for all to see.

Re:"and time runs backward as well as forward."

[Zero__Kelvin]

These will have been the same people arguing against the Universe having a creator. Get your friggin' present future tense right! Hath the great Architect Vandaley tought you nothing in the creation of this Earth?

Re:"and time runs backward as well as forward."

[Zero__Kelvin]

"No. They aren't "arguing against" the Universe having a creator. They simply have no evidence FOR one, so they dismiss the idea."

Look, I'm no creationist, but claiming there is no evidencethat points toward a creator is pretty absurd. I agree there is no proof, or after all why would I doubt it, but there is certainly evidence.

Re:"and time runs backward as well as forward."

[Anonymous Coward]

... but there is certainly evidence.

Such as?

Re: "and time runs backward as well as forward."

[master_p]

There is absolutely no evidence whatsoever.

Re:"and time runs backward as well as forward."

[Anonymous Coward]

Actual scientific evidence, not fabricated subjective evidence.

Re:"and time runs backward as well as forward."

[Anonymous Coward]

With a purely physiological explanation such as cerebral anoxia for the experience, most patients who have been clinically dead should report one

Says who? For less unfounded claims I have rejected a paper for publication. I can't imagine how a reviewer let this slip.

That claim is like saying "If we dreamed all night every night, we all should report having dreams every morning", which is not only a baseless stupid statement, but an easy probable wrong one.

Re:"and time runs backward as well as forward."

[AmiMoJo]

We are now as far from Marty's 1985 start date as he was his original 1955 destination. Man, I feel old.

Re:"and time runs backward as well as forward."

[Anonymous Coward]

"No. They aren't "arguing against" the Universe having a creator. They simply have no evidence FOR one, so they dismiss the idea."

Look, I'm no creationist, but claiming there is no evidencethat points toward a creator is pretty absurd. I agree there is no proof, or after all why would I doubt it, but there is certainly evidence.

Thank you for clarifying your position that you're "no creationist", because you sure as hell sound like one. Having 0 evidence for something is absolutely reason enough to dismiss it -- until such evidence is presented, anyway. All the "evidence" that I've ever seen/heard that's been presented in favor of creationism boils down to: "It's complicated, therefore: god" -- which is total crap.

Re: "and time runs backward as well as forward."

[Zero__Kelvin]

You are an idiot who doesn't know the difference between evidence and proof.

Re:"and time runs backward as well as forward."

[rail2rail]

Old age is a luxury not afforded to many. Relish it.

Re:"and time runs backward as well as forward."

[perih60]

i enoyed your post , off subject i believe that those who study history , and not do their own research , behave the way you stated

Re:"and time runs backward as well as forward."

[Zero__Kelvin]

A creationist believes in the existence of a creator. I hold no such belief. It isn't that hard to understand. :-)

Re: "and time runs backward as well as forward."

[Anonymous Coward]

The fact that you state a strawman argument for there being a creator as the only argument just show that you are unqualified to judge the evidence. Before you can be qualified you first must know what it is. Second you add the conclusion "must be" to that strawman argument which complete invalidates your comment. You equate "there is evidence" with "must be so" which are the single most common strawman used.

Even worse. The comments that you reply to specifically states that it is not proven. Yet you go ahead and interpret the comment as a claim that it is proven.

Re: "and time runs backward as well as forward."

[Anonymous Coward]

The sentence isn't in present future, so why would he or she get that right?

Flux capacitor!

[mrego]

and this is the basis of the flux capacitor and all of time travel. About time it got discovered.

Re:Flux capacitor!

[Jumunquo]

Someone needs to tell Stanford to stop making donuts.

Re:Flux capacitor!

[Anonymous Coward]

I love bursting bubbles, so here goes:

Subatomic particles traveling back in time does not imply that humans can or will ever be able to travel into history and change it. A human being is the product of layer-upon-layer of "emergent phenomena," which means that reality as we experience it is several layers removed from subatomic reality as it appears to us.

We don't really know what these subatomic particles are doing, we just know that they appear to be able to be in multiple places at once, and our math is simplified if we represent the behavior as traveling back in time. Nothing about this implies that the past is some kind of place that you can go back to as you might go back to a shopping mall. It is a popular metaphor, but has *absolutely no basis* in scientific fact.

Time travel is, and always will be, the weakest of all science fiction plot devices.

Re: Flux capacitor!

[Anonymous Coward]

Time travel is, and always will be, the weakest of all science fiction plot devices.

But it's so much fun to think about!

Re:Flux capacitor!

[Zero__Kelvin]

"I love bursting bubbles, so here goes"

Well, you suck at it. Even as we speak I am gleafully anticipating the time when I will have looked back upon the future with a special gleam in my eye, knowing that some AC on Slashdot couldn't have burst my bubble, even back when I would soon be vulnerable to such slights such as he would soon be trying.

Re:Flux capacitor!

[perih60]

i agree :) posting outside the US = lower points

Explain to me like I'm 5

[mariox19]

where matter does not take form until it is observed

Don't we have an intractable Chicken-and-Egg problem here?

Re:Explain to me like I'm 5

[Archangel Michael]

This is not a chicken/egg problem. This is now a known scientific fact. The Beginning of the universe, according to this information, must have had an observer.

Re:Explain to me like I'm 5

[Gr8Apes]

Even if that observer is us, in the future, moving backwards.

Re:Explain to me like I'm 5

[Anonymous Coward]

Facepalm post of the day!

Re:Explain to me like I'm 5

[Lumpy]

We all know it had an observer, The Doctor goes back to watch it on a regular basis.

Re:Explain to me like I'm 5

[peragrin]

Yes but he always skips out the ending as it is to depressing.

Re:Explain to me like I'm 5

[U2xhc2hkb3QgU3Vja3M]

Time travel. Since my first day on the job as a Starfleet captain I swore I'd never let myself get caught in one of these godforsaken paradoxes - the future is the past, the past is the future, it all gives me a headache. - Captain Janeway

Re:Explain to me like I'm 5

[Anonymous Coward]

Not as depressing as your english.

Re:Explain to me like I'm 5

[aaron4801]

And since time runs backwards as well, you can observe the reverse from The Restaurant at the End of the Universe.

Re:Explain to me like I'm 5

[Anonymous Coward]

The chicken-and-egg "problem" is not intractable, even for a 5yr old : the egg came first. Ask a 5yr old what laid the egg, they will tell you "a dinosaur".

Re:Explain to me like I'm 5

[pushing-robot]

Explain to me like I'm 5

If you insist.

Re:Explain to me like I'm 5

[Anonymous Coward]

I don't think that's how it works. Matter can do its thing without an observer, but when it is observed (i.e., when it is interacted with... nothing to do with consciousness) the wave function collapses and it no longer exists in all possible states.
But what do I know?

Re: Explain to me like I'm 5

[Anonymous Coward]

Like a recursive function?

Re:Explain to me like I'm 5

[Anonymous Coward]

The Beginning of the universe, according to this information, must have had an observer.

That's not how it works. Lots of matter in the universe has no observer right now. It still exists, and does it's thing. It just does so in a quantum manner.

This is not any kind of evidence that the universe had an "observer"* at creation.

* note: if you subscribe to either the many-worlds theory or objective collapse theory of quantum mechanics, the question of an observer is irrelevant

Re:Explain to me like I'm 5

[ememisya]

+1 For Star Trek! Today we are all thanking the Dutch for bringing us one step closer to a secure Internet :D

Re:Explain to me like I'm 5

[Anonymous Coward]

Not as depressing as your English.

FTFY

Re:Explain to me like I'm 5

[Anonymous Coward]

i am the observer. the rest of you are just quantum fluctuations of my imagination.

Re:Explain to me like I'm 5

[jfengel]

It's not intractable, but it is a challenge. (Well, not "five"; I kinda hate that expression. But "scientifically interested layman" isn't beyond reach.)

Try it this way: Quantum mechanics rules are the "real" rules of the universe: objects don't have exact positions or locations. Rather, what you get is a wave that describes the object. One way to interpret that wave is that it predicts the probability that it could be at any particular place. The total behavior of the object is the sum of those probabilities. It really is in every single place, all at once, though "more" some places than others. These waves can even cancel out. That's very much at odds with what we expect.

Here's the thing with probabilities: the more of them you add up, the more they behave like the average. That is, there's a lot of uncertainty in the roll of a 20 sided die. But you know that if you roll it a thousand times, the average is going to be very close to 10.5.

Real-world objects contain far, far, far more than a thousand objects. If you work the sum of the quantum waves for that many objects, what pops out is remarkably like plain classical physics. So, everything you see looks like ordinary physics.

But if you design your experiment carefully, you can make some of the quantummy behavior show up. The most classic one is the two-slit experiment: you restrict the particle's path to one of two places, and you get interference waves. But if you modify the experiment so that it is interacting with large-scale objects like a detector somewhere in the process, the waves vanish. (A detector is something that has large-scale changes between the particle's presence and the particle's absence.) The confusing part is that you can put the detector in places where you wouldn't expect it to have an effect, but since the particle is "everywhere", it affects it in counterintuitive waves.

Proving that for certain turns out to be tricky. The difference between "the particle really is (partly) everywhere at once" and "the particle is actually in only one place, but you can't tell" is pretty subtle. You can show it by carefully counting up "entangled particles", where the two probability waves are linked. It would be natural to think that particles were exchanging information to maintain the linkage, faster than the speed of light, but the quantum rules actually rule that out. Proving it for certain is hard, since you're talking about very tiny things and very fast speeds. We actually have been doing it for decades, but since it's so hard, there were usually loopholes. This experiment finally nails the last of them shut.

The solution to the chicken-egg problem lies in the behavior of the sums: big objects behave like you expect them to because the probability of them not doing so becomes vanishingly small. There's still some fiddly bits: that "vanishingly small" isn't quite zero and nobody exactly knows where it goes. Some say "another universe"; others (like me) just put our fingers in our ears and say "I don't know but shut up and calculate la la la".

Re: Explain to me like I'm 5

[Dareth]

http://www.gifbin.com/982288

Re:Explain to me like I'm 5

[jalet]

Thanks !

Re:Explain to me like I'm 5

[lgw]

Don't we have an intractable Chicken-and-Egg problem here?

The difficulty in understanding is mostly in how the experiment is described. This is the latest in a series of increasingly technical experiments exploring pretty odd corner cases in quantum theory. They're important because they close the last loopholes, the last excuses that anyone who really understands the field had in believing in any sort of classical underlying reality.

There's no time travel here. There's no FTL communication here. Either of those would actually invalidate the experiment. The point of this all is: you simply can't explain these results classically. And that's nothing new - there's a long list of such results.

Here's any easier experiment to understand. Take 2 polarized filters, and measure the amount of light that gets through as a function of the angle between them. With a classical model of polarization, you'd expect it to fall directly with the angle, but instead it falls of as cos^2 of the angle. Most of these Bell Inequality experiments are very similar in principle, they just use 2 entangled photons or electrons instead of one beam of light passing through two filters in series.

The part about "hidden variables" vs "spooky action at a distance" is only relevant if you're trying to explain the result classically. If you give up notions of a classical underpinning to physics, if you accept that e.g. the spin polarization of an electron simply isn't about the axis of a spinning ball (a ball with a bar magnet inside), then there's nothing surprising here. Sure, it's weird, but it's weird in the exact same mathematical way as the beam of light passing through 2 polarizing filters.

This all just shows that the idea of an electron or photon as any sort of particle, like a dust mote only smaller, is simply a flawed metaphor that you can't reason from. But since there was no reason to expect them to be that way, it's not even that weird.

(What's really weird, though, is that of you take 2 polarizing filters at right angles, such that no light gets through, then stick a third between them at a 45 degree angle, then it's as bright as one filter alone.)

Re:Explain to me like I'm 5

[devnulljapan]

This is not a chicken/egg problem. This is now a known scientific fact. The Beginning of the universe, according to this information, must have had an observer.

"You're very clever, young man, very clever- but it's turtles all the way down!"

Re:Explain to me like I'm 5

[Anonymous Coward]

You're misrepresenting the meaning of "observer". QM does not say a sentient being is required for an "Observation" to take place. Think of all the QM going on throughout the universe with no-one observing it.

Yeah, huh?

Dumbed-down science journalism again.

Re:Explain to me like I'm 5

[Anonymous Coward]

The need for an observer in QM is still a controversial point, as I understand, including a necessary bit of vagueness about what "observer" even means. It is not fair to say that "it has been proven that all interactions require observation by at least one conscious, thinking being before they actually happen." That might be a popular layman's takeaway, but it is not an accurate representation of the state of the theory.

I would venture to say it more like this:

Our simplest and most-comprehensive models of the universe still include a nebulous concept of "observation." We are still working on getting that clarified, but until we can do that there is still quite a lot of other aspects of the theory that we can still experimentally demonstrate and refine.

Re:Explain to me like I'm 5

[Ramze]

No. You're taking "observation" too literally. A better explanation is -- nothing exists in any definable state until it interacts with something else.

That's what "measurement," "observation," and "detection" generally mean -- some sensor capable of being triggered by an event was triggered... something in a quantum state interacted with something else and the wave function collapsed.

No conscious observer is required. Just stuff interacting with stuff.

Re:Explain to me like I'm 5

[Arkh89]

Take 2 polarized filters, and measure the amount of light that gets through as a function of the angle between them. With a classical model of polarization, you'd expect it to fall directly with the angle, but instead it falls of as cos^2 of the angle.

The classical E.M. theory perfectly predicts the cos^2 term. See Malus law.

What's really weird, though, is that of you take 2 polarizing filters at right angles, such that no light gets through, then stick a third between them at a 45 degree angle, then it's as bright as one filter alone.

No, you would have less power than a single polarizer. This also very well explained by Jones calculus.

Re: Explain to me like I'm 5

[Anonymous Coward]

I know what yu're trying to say, but it's wrong. There never was a "first chicken", it is a continuum.

Re: Explain to me like I'm 5

[Anonymous Coward]

There you go with that fag talk again...

Re:Explain to me like I'm 5

[Mr.CRC]

In other words, the only thing that we can say for sure about anything is what it does, not what it is.

Re:Explain to me like I'm 5

[KGIII]

For once, my signature is applicable. Don't worry, I changed it tomorrow to be this today. (I'll take the sleek black spaceship, thanks. It looks more interesting and the result is highly improbable.)

Re:Explain to me like I'm 5

[KGIII]

I understand that we don't need to observe it but that it can change behaviors based on the state of observation at the time - like the photons through the slits that misbehave when you leave the room.

Re:Explain to me like I'm 5

[KGIII]

Go watch Brian Cox. Do it right now. Do not delay. There are many choices. Start with The Wonders of the Universe. Get the book. He's got an excellent way of describing things. He does one at the Royal Academy of Science (I think it was their traditional Christmas thingie) that is *very* good. Just go watch him. Seriously. All I watch, for the most part, is documentaries - they're entertainment and not educational for me. He is, by far, one of the best - if not the best. He's like Attenborough for Physics, Astrophysics, Quantum Mechanics, etc...

Go watch him now. Right now.

Re:Explain to me like I'm 5

[Boronx]

What's an observer?

Re:Explain to me like I'm 5

[n3r0.m4dski11z]

"Even if that observer is us, in the future, moving backwards."

aw fuck dude, i should not have just watched back to the future 2 and smoked a bunch of weed before reading that.

We see the past, so its there. I think so I am, makes it so. Life and the universe is an invented illusion, and that is reality. I cant say i know enough quantum mechanics to all but interpret wildly on what you said though.

Re:Explain to me like I'm 5

[Anonymous Coward]

That is philosophy, not physics. Determinism is the foundation upon which science rests. Without determinism you cannot test a theory.

It is like saying that the tree in the woods didn't fall if it didn't hit ground. It is technically correct, but completely avoids the question asked.

Re:Explain to me like I'm 5

[Zero__Kelvin]

"This is not a chicken/egg problem ... The Beginning of the universe, according to this information, must have had an observer."

But nothing says if that observer was a chicken or an egg.

Re: Explain to me like I'm 5

[Zero__Kelvin]

That's not recursion, actually.

Re:Explain to me like I'm 5

[lgw]

Classical EM theory predicted no such thing. It was measured as such, and incorporated in theory, without any real explanation from first principles as to why. And it wasn't obvious that electron spin polarization would work the same way.

If you start reasoning about elections as spinning bar magnets that precess along the axis of measurement, then think about measuring them at one angle and the change you'd get the same result when measured at another, you're lead to the wrong answer. Electron "spin" is a metaphor.

If you think of photons as particles, you also get a similar wrong answer (heck, it's hard to explain why polarization even happens to a particle). No intuitive mental model is going to explain the 3-polarizer case, or similar experiments where the polarization of light changes without any energy input.

Re:Explain to me like I'm 5

[twosat]

One of the most famous of the late Monsignor Ronald Knox's witticisms was a verse built on the Berkleyan idea that things exist only when they have an observer:

There once was a man who said: "God
Must think it exceedingly odd
If he finds that this tree
Continues to be
When there's no one about in the Quad."

This promptly drew the anonymous reply:

"Dear Sir, Your astonishment's quite odd;
I am always about in the Quad;
And that's why the tree
Will continue to be
Since observed by Yours Faithfully, God."

Re: Explain to me like I'm 5

[sce7mjm]

Personally I don't rate Brian Cox as much as some. I've read his book on quantum stuff. Can't even remember what it was called.

He's analogies for waves to clocks was confused and did nothing to explain interference properley.

Feynmans qed, is the one to read. Trying to rewrite it is a mistake that keeps getting made.

The bbc have a love affair with Brian because he is popular and mums think he is sweet.

Playing with salt shakers and drawing in the sand does not explain angular momentum. Standing a kid on a wheelychair and spinning them with weights in the hand does. (or observing a ballerina).

Watching him rolling balls on a rubber sheet trying to explain space time makes me weep. And it uses the phenomena you trying to explain in the description of how it works. Wtf?

Stop dumbing down my science...! It's hard enough as it is, without floppy haired musicians on an ego trip brushing over the complicated stuff.

Re:Explain to me like I'm 5

[jandersen]

Quantum mechanics rules are the "real" rules of the universe:

No - in fact, we know that QM is imperfect; being a scientific model implies that much. It is in many ways the fundamental axiom of science, that we can not prove truth through observation, we can only disprove false predictions. Don't get me wrong - QM is a marvelously robust theory, but unfortunately, so is GR, and the incompatibility between them is a very strong indicator that there is a lot of reality that is not covered by either theory, and that we probably have to find a starting point that is alien to both theories, to unify them.

One of the strengths of GR is its logical simplicity; QM lacks that in so many places. There are too many wooly constructs that lead people's thinking astray, like the idea that it is somehow fundamentally impossible to know details below a certain limit (Heisenberg) or that things only exist if we observe them - or that "everything is probabilistic in nature". The truth of the matter is, I bet, that these things are artifacts of the available methods. When you rely overwhelmingly on statistical methods for analysing your observations, then of course you end up thinking in terms of probability, which s no more than 'predictive statistics', in many ways. And when you observe by throwing wave-forms at each other to see how they interact, then of course there will be limitations to how well determined your observations will be - it is hard to observe detail finer than the wavelength, for one thing. And the idea, that things only exist when somebody observes them is a wild overinterpretation of both theory and observations.

We really, really need to clear our minds of this sort of quasi-religious thinking, because the unhappy thing is that it stops us from even looking outside the box.

Re:Explain to me like I'm 5

[Anonymous Coward]

The classical E.M. theory perfectly predicts the cos^2 term. See Malus law [wikipedia.org].

That's for one linearly polarised photon, at an angle phi to the polarizer, has a probability cos(phi)^2 to pass through that polarizer. These experiments deal with the probability of two photons passing passing through two respective polarizers, with the polarizers inclined at an angle phi to each other.

QM predicts the photons will both pass through with probability 1/2 cos(phi)^2

Malus' law predicts the photons will both pass through with probability 1/8+1/4 cos(phi)^2.

The second result apparently doesn't match with experimental observations. That said Bell's theorem doesn't apply to it because it's probabilistic, not deterministic.

Re:Explain to me like I'm 5

[Anonymous Coward]

"If you think of photons as [SINGLE] particles, you also get a similar wrong answer"

Quit thinking of photons as some sort of indivisible single thing!
You know the two slit experiment, you know they turn the light source down till photons come out one by one. The interference fringe still happens, so the light is still going through both slits, so they're not packets.

But of course it isn't a packet! You are using electronic detectors, the basis of those is the light hits the electron, promotes it, kicks off an outer electron and you measure that. So you need a quantum of energy to do that, and so you could only ever detect a light as fixed quantums! i.e. Photons.
But the two slit experiment means light MUST go through both slits and therefore it DOES.

It's not a packet, and its not a single indivisible dipole, yet it has dipole effects (responding to magnetic fields), it has net spin, and it behaves like waves.

So its water, well something very similar, its a cloud of dipoles.

Re: Explain to me like I'm 5

[Anonymous Coward]

"Stop dumbing down my science" you say in a thread titled "explain it to my like I'm 5". You probably aren't the target audience.

Re:Explain to me like I'm 5

[JohnStock]

and Spain and England.

Re:Explain to me like I'm 5

[JohnStock]

"Think of all the QM going on throughout the universe with no-one observing it." and had not had it's wave function collapsed surely?

Re:Explain to me like I'm 5

[Anonymous Coward]

If a particle can be everywhere, then how is there even such thing as an "object"?

Does this imply that gravity cannot be everywhere and therefore that is what defines an object?

Is an object falling to the ground due to increasing probability that the object is sitting on Earth?

(sorry, I realize not all of these thoughts make sense)

Re: Explain to me like I'm 5

[Anonymous Coward]

Yeah you're probably right!
Just a bit fed up of watching popular types (Stephen Fry, Brian Cox among others) reeling off information like they understand it, whilst avoiding the unknown or debatable issues that are still being researched.

ITS TRUE COS COX SAYS SO!

Re:Explain to me like I'm 5

[JigJag]

This explanation to me makes sense, but more importantly it confirms the idea of hyperdimensionality, akin to how a point relates to a line, a line to a surface, a surface to a volume, and here a volume to a wave cloud.

Re:Explain to me like I'm 5

[Waccoon]

It would be nice if the term "observation" was clarified in every explanation of the double slit experiment. I'm sick of every explanation including the phrase, "as if it knows it's being watched", trying to make real science feel more like magic, rather than the other way around.

Re:Explain to me like I'm 5

[mariox19]

Thank you.

Re:Explain to me like I'm 5

[mariox19]

Thanks. This makes me think of Plato's Cave. In other words, we live here in the "big" part of the universe. That's what we observe, and in terms of concepts, that's our frame of reference. And Newtonian physics applies really well in describing what goes on here, and in a way that appeals to our everyday concepts. But, as we turn our attention to what goes on in the "smaller" corners of the universe, and try to understand what we observe using the concepts from the frame of reference we live in, our analogies break down. Is that sort of what you're saying?

Re:Explain to me like I'm 5

[Anonymous Coward]

This.

Re: Explain to me like I'm 5

[Anonymous Coward]

More Copenhagen bullshit from people who do not understand Quantum Field Theory. This is what we get for teaching students simplified models to make calculations easier.

Re:Explain to me like I'm 5

[jfengel]

Sorry; I was working on a "scientific layman" answer. It's full of errors, inconsistencies, and exaggerations. Making it more correct would have made it even longer and harder. I settled for putting "real" in quotes and hoped that people who understood the science would grasp why I did that.

Re: Explain to me like I'm 5

[KGIII]

You know it's not meant to be a study but is just a source of passive learning, right? If you're basing the entirety of your education on documentaries then you're going to be sorely lacking. If you're wanting more difficult material then he has plenty of his lectures available online. I think it's great to make science available to the masses - even if that means skipping some of the details. (What I don't like is when they present theories as fact.)

Re: Explain to me like I'm 5

[Anonymous Coward]

Parent AC here. Totally agreed.

Re:Explain to me like I'm 5

[david_thornley]

Actually, we're in the "medium" part of the Universe. In our daily lives, we can disregard relativity entirely except for gravity. The Universe gets non-intuitive at larger scales, although not as weird as at small.

Re:Explain to me like I'm 5

[Anonymous Coward]

No conscious observer is required.

Although, it'd be pretty tough to design an experiment that didn't include one somewhere at some point...

Re:Explain to me like I'm 5

[perih60]

the two slit results . has anyone ever looked at this from the point of view , taking spin and quanta into consideration ? how many of my fellow members have read the works of Prof. Roger Penrose ? he had the maths chair at Oxfort for a long time . lastly i like this site , however it seems to me that if anyone outside the US posts , they do not get as many points , regardless

Re:Explain to me like I'm 5

[strikethree]

"A better explanation is -- nothing exists in any definable state until it interacts with something else."

How can something interact with something else if it is not already in a definable state? Is there some minimum zone around all "objects" that permit interaction to start and cause the collapse of the wave function only when that boundary is crossed? Would that zone be one wavelength? If so, what determines the wavelength of a particular object? Its energy state?

Re:Explain to me like I'm 5

[jandersen]

Yeah, I know. I'm just this cranky, old git who would probably speak out loudly and with authority against even an obvious truth, if somebody else said it ;-)

Re:Explain to me like I'm 5

[perih60]

at the start of my very limited formal education , i was told that , arithmetic , the decimal system have been proven beyong all doubt . do not question ! 1+1=2 , fine no problem , i did as told . after i finished my home work , drew a nice border around my work , within this border i put 1000+1000=2000. boy did i get into trouble , " you do not know what 1000 is " " do not get ahad of yourself " " we tell you the problems you are to solve " ! Now i look at things differently because , the decimal system starts at 1 , ..9 , 10 , i was confused beause all of a sudden the digit 0 came into play , ill defined . so os i believe in evolution ( not made up my mind re god ) i know that a mammal starts its life , half the genes from the ova , half from spermosa , to make 1 mammal . i am convinced thatmaths is tought wrongly , every digit , symbol , consept MUST BE COMPREHENDED , OR CONFUSION BEGINS ! knowledge on it's own does not equate understanding !

Re: Explain to me like I'm 5

[Anonymous Coward]

It's always hilarious when falsely claim that something isn't good English, when in fact it is. Usually exposing that they think English is the language of America, ignorantly applying US English rules to the original language. A language that has different grammar pending where in the UK you ask.

Re: Explain to me like I'm 5

[Anonymous Coward]

No it is not and never was. Determinism is an philosophy with has a great influence on science, but science is not based on it. If you ask most scientists they will not agree that determinism is in any way a foundation of science. The scientific method is the foundation of science and it is in no way dependent upon determinism.

Classical physics on the other hand do depend on determinism but as we know by empirical evidence - classical physics do not apply to quantum physic. And classical physics is A science but it isn't "science" as in all of science.

It all boilers down that to in most everyday situations Newtonian physics, which is deterministic, explains things well enough. As a simplification. And when Newtonian physics ain't enough Einsteins equations often works well enough. But there are plenty of empirical evidence that doesn't comply with those as well.

So while determinism is an important simplification of reality science doesn't depend on it.

I've been waiting for this!

[Locke2005]

Does this mean faster than light communication is actually possible? Maybe the best way to connect with extraterrestrial intelligence is to figure out how faster than light communication works, then make a call. What do you have to do to pair the particles to begin with?

Re:I've been waiting for this!

[darkain]

Just press the red button on each and wait for their red LEDs to start blinking to pair the particles.

Re:I've been waiting for this!

[U2xhc2hkb3QgU3Vja3M]

Maybe the best way to connect with extraterrestrial intelligence is to figure out how faster than light communication works, then make a call.

Why? Who you gonna call?

Re:I've been waiting for this!

[Arkh89]

No, with entanglement it would seem that you cannot force one particle to a state so that the other is switching as well. Thus, you cannot effectively use this as a communication channel.

A very crude picture can be stated as the following : you send two letters containing the same unique number (0...9) to both Alice and Bob (who also know this rule). When Alice opens her letter and reads the number, she knows that Bob has the same number but she cannot use that to communicate a particular number to Bob directly.
WARNING : This explanation is using the hidden variable model which is wrong, as the EPR paradox/Bell's inequality and these researchers are proving. But this is the only simple explanation I know (with my limited knowledge of QM) to convey the fact that entanglement can not be used as a communication channel.

Re:I've been waiting for this!

[myrdos2]

Not that we know of. If you measure your particle, you know the fellow on the other end will read the opposite measurement. It's like having random number generators at each end that are perfectly synchronized, but always produce inverse results.

You can use it for unbreakable encryption though, by treating your random numbers as a symmetric key with unlimited length. The person at the other end can deduce your key from his own measurements, without ever having to send the key over the channel.

Re:I've been waiting for this!

[Kartu]

Nope, as there is:
https://en.wikipedia.org/wiki/...

which states that, during measurement of an entangled quantum state, it is not possible for one observer, by making a measurement of a subsystem of the total state, to communicate information to another observer.

Re:I've been waiting for this!

[Lumpy]

Knowing how humans work, we will make a UDP broadcast call giving our location with "hello" and a lot of annoying children in different languages saying hello.

This will cause a galactic armada to come here and obliterate us for messing up the last half of the season finale of "glip Glopr the unstoppable".

Re:I've been waiting for this!

[DahGhostfacedFiddlah]

I've never actually heard a convincing argument as to why this explanation is wrong. It seems to describe the Bell inequality experiments perfectly.

Re: I've been waiting for this!

[Anonymous Coward]

Even if such a mechanism was discovered, how would we determine the protocol with which to "call"? Perhaps we are already receiving communication from extraterrestrials without realizing it. Akin to steganography, it could be encrypted (with some yet unknown algorithms) and/or spread over multiple spectrums, appearing hidden in background radiation.

Re:I've been waiting for this!

[Fire_Wraith]

Don't be silly. They're just here to construct a hyperspace bypass, which will require the demolition of the Earth.

Oh, and don't bother complaining. The plans have been on file at the local office in Alpha Centauri, if you wanted to file a complaint, you should have done it then.

Re: I've been waiting for this!

[baker_tony]

Ghostbusters!

Re:I've been waiting for this!

[U2xhc2hkb3QgU3Vja3M]

If we know it's the inverse result, can't we use it anyway? Using binary as an example, if one end reads "1" then it means the other ends reads "0".

Re:I've been waiting for this!

[Anonymous Coward]

The reason it is wrong has to do with more subtle aspects of the experiment - think of it as that the distribution of the numbers over a bunch of experiments is different if the central sender is choosing the numbers at random versus the numbers being selected by quantum entanglement. Thus the analogy is not exact (none are), but it does a great job of explaining why this does not enable faster than light communication.

Re:I've been waiting for this!

[Anonymous Coward]

Use it for what? It's a random string of binary digits. I guess you'd know exactly what the random string of binary digits was on the other end. However that is not useful information.

Re:I've been waiting for this!

[Anonymous Coward]

No... information does NOT travel faster than the speed of light...

Re:I've been waiting for this!

[Spaham]

Actually it has been proven that no signal can be passed between the two events, even though they seem to be linked.
So no communication or data.

Re:I've been waiting for this!

[Anonymous Coward]

I knew you were going to say that, before you said it.

Re:I've been waiting for this!

[ClickOnThis]

Does this mean faster than light communication is actually possible?

Short answer: no.

Longer answer: entangled particles can only be observed to be in a state, they can't be placed in a state.

The coin analogy is a good one. Imagine that you and a friend a long distance away have two "magic" coins that are guaranteed to show opposite sides: one comes up heads, and you know the other comes up tails, and vice-versa. You can flip your coin, see it come up heads, and you know instantly that your friend sees tails. But here's the catch: you can't control which face shows up. You can only observe it. So, there's no way to send information through the coin-flips.

Re:I've been waiting for this!

[sconeu]

Said armada will, due to a scaling error, be promptly eaten by a small dog.

Re:I've been waiting for this!

[harryjohnston]

Bell's Theorem.

Re:I've been waiting for this!

[PacoSuarez]

xkcd just covered this a few days ago: https://xkcd.com/1591/

Re:I've been waiting for this!

[PacoSuarez]

This is easier for me to grasp in the many-worlds interpretation of quantum mechanics. There is a universe in which Alice is holding "0" and Bob is holding "1", and another universe in which Alice is holding "1" and Bob is holding "0". Those two universes separate the moment Alice (for example) looks at her bit. At that point she is certain that Bob got the opposite bit.

Re:I've been waiting for this!

[DahGhostfacedFiddlah]

I've read a number of accounts of the Bell Inequality experiments, and I still don't see how it doesn't boil down to "Alice got X there for Bob got Y", or at least "Alice got X, therefore Bob has a Z% chance of having Y".

The numbers definitely jive with what you'd expect from wave-like phenomena, not particles. But I've never seen any good reason to believe that observation plays a causal part in the system. It's more like observing things locally can tell us what happened remotely - but that's just normal backtracking.

Re: I've been waiting for this!

[Anonymous Coward]

But you can control the flip event (observation). So I'll observe my Particle three times for yes, five times for no. Keep an eye on it!

Re:I've been waiting for this!

[Boronx]

Hold on though. If I don't actually look at my coin (leave it spinning). Isn't my friend's coin still spinning? Can't we tell that statistically?

Let's say we're firing off entangled electrons. We have a splitter based on the spin of the electron. We redirect the split electron beam at the same target. If our friend is *not* measuring spin with his entangled stream, won't our beam interfere with itself? Won't that interference go away if our friend starts to measure?

Re:I've been waiting for this!

[Zero__Kelvin]

"But here's the catch: you can't control which face shows up. You can only observe it. So, there's no way to send information through the coin-flips."

How much do you want to bet?

Re:I've been waiting for this!

[Anonymous Coward]

What you're missing here is that Alice has NO control over what she'll read, so she can't use it to send a message, she can only use it to know what the other person has read or will read (you can't even know who collapsed the wave function) without talking to the other person.

Re:I've been waiting for this!

[Anonymous Coward]

That's not how it works. You toss your coin and you get heads, and then you know that your peer will read tails when he or she tosses the entangled coin. In fact, if your peer tossed the coin before you tossed yours, you will get the complementary result of what your peer got.

Re:I've been waiting for this!

[Uecker]

The crucial piece you are missing is that the results depend on the type of measurement Bob and Alice perform. If you want to simulate this on a classical computer, to get the correct statistics you need the information of the type of measurement performed on the other side. In other words, if you instead of entangled particles send two classical computers to alice and bob which should simulate results with correct statistics, those computers need to communicate to achieve this.

Re:I've been waiting for this!

[JohnStock]

Even if possible to send info. You'd still have to take that particle there first at velocities c. It's like star gates in sci-fi, you need to travel there first to build the gate to allow FTL! lol This is why warp drive is vastly superior :P

Re:I've been waiting for this!

[DahGhostfacedFiddlah]

Last time I looked into this (and it's been a while), that's true if you send the computers from a central point and they arrive unmodified at their destination.

But all of the Bell Inequality experiments I've seen pass the light/electrons through a filter or polarizer. Once you take into account the effect of the filter on the particles, it becomes a simple backtracking problem again.

Guh - I know I'm in the minority on this - I really should just run the math myself and see if I'm missing anything.

Re:I've been waiting for this!

[locofungus]

Part of the reason you've never heard a convincing argument is that there isn't a classical way of describing this.

Imagine Alice has some "magic" ink.

She can write in blue, yellow, magenta or green or combinations of them.

However, these inks are "magic" in that blue and yellow exactly cancel each other out. If you mix the blue and yellow inks together you're left with an ink in which ever colour there was the most of. It's not paler. If you mix in exactly the same quantities then the ink disappears completely.

Ditto magenta and green.

Alice mixes an ink colour together from these four inks. As some inks cancel each other out we can define the final colour by one number being the angle the final colour makes on a circle with magenta at the top, green at the bottom, blue on the left and yellow on the right.

These magic inks have another peculiar property. You can only ask "yes/no" questions to tell what colour they are and the act of asking the question forces the ink to the appropriate colour.

So, if you have a yellow ink and ask "is it yellow" then the answer is yes - with 100% probability.

If you ask "is it blue" then the answer is no - with 100% probability.

Things get weirder when you ask "is it green". If the answer is yes then the ink is green - so it changes from yellow.

Remember that these magic inks disappear if you mix eactly the same quantity of magenta and green. So if you have an ink it must be either magenta or green. Otherwise the ink would have vanished completely and there wouldn't be any ink to be asking questions of.

If the answer to "is it green" is no then that means the ink must be magenta instead - so a no answer to "is it green" turns the ink magenta.

Because a yellow ink is neither green nor magenta in reality but the "is it green" question requires an answer, the answer will be randomly yes or no with 50-50 probability.

N.B. Because the ink actually changes colour after the first "is it green" question repeatedly asking the same question will get the same answer.

But you don't have to limit yourself to these two axes - instead we can ask "is it a 50/50 magenta/yellow mix. If the answer is yes then it really is a 50/50 magenta yellow mix. If the answer is no then it's a 50/50 blue/green mix instead.

If the ink started out as yellow (we asked "is it yellow" and the answer was yes) and then we ask "is it a 50/50 magenta/yellow mix" then we're more likely to get a yes than a no answer.

If we make the measurement we find that the probabilty of getting a yes answer is the square of the cosine of half the angle between the initial colour and the question we ask.

Now to Alice, Bob and Carol's problem. Does the ink "know" the answer to any question you can ask of it.

Let's say that Alice used yellow ink.

If Bob and Carol both do the "is it yellow" test then they both get a yes answer.

But instead, lets assume that they both do the "is it green" test. We've already established that the answer to this is yes or no with 50/50 probability. So we can get yes/yes, yes/no, no/yes and no/no as the four possible combinations of answer. But... where it gets weird is where the ink on the two letters is entangled. Bob and Carol both get the same answer - i.e. the only answers are "yes, yes" and "no, no"

This is what entangled means - if you make the same measurement you get the same answer (where same actually means opposite in most experiments)

(in practice you have to repeat the experiment over and over again to establish that B&C always get the same answer to whatever question they ask. To avoid problems where the ink "knows" what test will be done in advance when Alice mixed it they randomly decide what test to do at the last possible moment and then compare answers and only use the cases where they randomly chose the same test to do)

Lets assume that Alice writes in yellow ink that is entangled between Bob and Carol's letters.

If you actually work out the maths

Re:I've been waiting for this!

[Uecker]

I don't get quite get what you man by simple backtracking problem....

The math gets much nicer if you look at GHZ states with three particles. I am not sure if this is accessible to experiments yet, but the interesting effect becomes very clear..

Re:I've been waiting for this!

[Anonymous Coward]

You may not be able to control the "flips" but you can use the coin toss to synchronize an event so that activities take place at the exact same time.

Re: I've been waiting for this!

[amRadioHed]

The other person doesn't have any way of knowing that you made your observation before him.

Re:I've been waiting for this!

[Anonymous Coward]

You may not be able to control the "flips" but you can use the coin toss to synchronize an event so that activities take place at the exact same time.

You don't need magic coins for that. Just two clocks.

Re:I've been waiting for this!

[locofungus]

I don't know what you mean by "backtracking" but you cannot reproduce the results of QM using a computer without communication between them.

Setup 1000000 experiments where a "particle" is in state |1> Orthogonal states are |+> or |->

Calculate hidden variables for the results of measuring state |a> |1> and |b> where |a> is slightly perturbed towards |+> and |b> towards |-> by angle theta.

"Copy" the states onto another computer so that they are "entangled" (strictly this would mean that one computer will have |1> or |0> randomly and the other will have |0> or |1> respectively but it doesn't actually matter for showing Bell's inequality.)

Send the "entangled" states to two parties, Alice and Bob

Each of those parties decides to measure |a> |1> or |b> randomly.

Where Alice and Bob both measured the same state they got the same result (due to your precalculated hidden variables)

Where one measured |1> and the other measured |a> the number of anti-coincidences should be 1-cos^2(theta/2).

Ditto for |1> and |b>

So far, so good.

But now consider the case where one measured |a> and the other measured |b>. The upper bound on the number of anti-coincidences is 2-2cos^2(theta/2). However QM requires 1-cos^2(theta) which is roughly twice as big for small theta.

Re:I've been waiting for this!

[david_thornley]

As an interested amateur, let me try.

The two-card model is sufficient to explain why quantum entanglement can't be used for FTL communication, but that's as far as you can safely take it.

There's things you can do with electrons and such that you can't do with cards. If we use electrons entangled so their spin is opposite, we can do other things than just observe their spin. Since the spin measurement is relative to some direction, Alice and Bob can measure in different directions, and later they can get together and talk about the correlations. There's other weird stuff you can do.

Distance?

[Viol8]

Spooky action at a distance is only spooky if one assumes distance is real and not an emergent property of a projected/holographic universe. In the same way in a computer simulation/game the distance between objects in no way represents the "distance" between them in the computers memory, perhaps our universe works at a similar level of abstraction.

Re:Distance?

[Anonymous Coward]

I'm not familiar enough with the physics to fully understand but I kinda understand what you're suggesting. Any chance you could rephrase it in more layman-y terms?

I'm being 100% serious. The concept of distance not being 'real' is intriguing to me, because it would 'fix' the problem of faster-than-light travel but distance is such a tangible thing that I want to understand more.

Re:Distance?

[Locke2005]

That was a thought I had as well, that this provides further evidence that we are actually living in a simulation instead of a "real" universe. I've heard the theory that the universe is not 3D but actually a holographic projection of a 2 dimensional universe, but in that case it seems like there would still be propagation delays for communication of information. My previous belief that we are living in a simulation was based on my being told that positions in space and time are inherently quantized; in a "real" universe, shouldn't everything be analog, i.e. infinitely variable? Of course, I'm not sure about the proof of quantization either.

Re:Distance?

[DogDude]

You're right. It's also only "spooky" if time exists as we perceive it to.

Re:Distance?

[pr0t0]

I've always assumed that the "distance" was merely due to our observations in three-dimensional space, but quantum entangled particles are "touching" at some higher level dimension. It's a guess.

Re:Distance?

[Anonymous Coward]

"that this provides further evidence that we are actually living in a simulation instead of a "real" universe."

It's your definition of what a 'real' universe is that's faulty. Get your head out of the matrix, we're not in a simulation, it's just the the Universe is quite different from what it appears to be.

Re:Distance?

[sexconker]

We have not seen things communicating with each at speeds greater than c. Entanglement is not communication.

The "holographic universe" "theory" is a joke. Real holograms occupy 3 dimensions and require 3 dimensions to be projected onto as well as observers in a space to experience them.

The "simulated universe" "theory" is a joke. Real computers occupy 3 dimensions and speed is determined by physical location (RAM closer to the CPU is accessed more quickly). They may not correlate to the position of objects in the virtual world, but the effects would either be observable for all objects (entangled or not) or not observable (because the simulated universe is blind to such effects since a reasonable simulator would wait until all of its fetching was done before processing the next universal tick).
If your claim is that entanglement manipulates the physical position of data in memory (thus causing the effects to be observable for entangled objects but not other objects), then you've effectively broken out of the simulation. Then you're at the point where entanglement isn't a thing, it's just what you call the effects of moving memory in your simulator, which is part of the actual universe.

Neither of these "theories" are theories. They're baseless, untestable conjectures that a 14 year old thinks up while taking a shit.

Re:Distance?

[DogDude]

You seem to think that these theories are meant to be taken literally. You might want to do some more reading on the subject. People much smarter than you have been thinking about this for decades.

Re:Distance?

[Anonymous Coward]

Which is why teleport hacks that come with some trainers work to begin with!

Re:Distance?

[Mascot]

Except there are observations supporting what we'd expect to see if it were a simulation. Kinda. It's highly speculative and involves string theory, but still.

https://www.youtube.com/watch?...

Re:Distance?

[Tablizer]

Spooky action at a distance is only spooky if one assumes distance is real and not an emergent property of a projected/holographic universe. In the same way in a computer simulation/game...

Perhaps the entire Universe runs on Hillary's home server. No wonder the 'ghazi committee is so determined.

Re:Distance?

[ceoyoyo]

Entanglement IS communication, in the proper sense of the word. You cannot use it to send a message, but entanglement without hidden variables implies that information is exchanged between particles.

The holographic universe hypothesis is so named because of it's relation to the principle of holography. Also, your assertion that "real holograms occupy three dimensions" is incorrect. A hologram encodes two dimensional interference patterns, which can be used to create a 3D (appearing) image when properly lit. The encoding medium itself may technically be 3D (as in, the thinnest possible film is still technically 3D) but the holographic information is two dimensional.

You know, the many PhD physicists who work on the holographic hypothesis might know a thing or two you don't.

Re:Distance?

[ememisya]

It's probably more like a two ended whirlpool, like a really tiny wormhole. It just doesn't break apart until it's "measured".

Re:Distance?

[tnk1]

Yes, but why do you think a "real" universe wouldn't be quantized? Having only seen one universe, our own, what evidence do we have of this scenario being somehow not basic?

The fact that it resembles what we do in computer simulations does not imply anything about the reality of the universe. It may be the other way around: simulations work the way they do because the real universe is naturally quantized.

It is an interesting and possibly even correct assertion that someone is running us as a simulation. But then what would the world of the "people" who are running the simulation look like? Are they in a simulation too? Are we all inferior projections from the original world of perfect forms? All possible, of course, but that's kind of like it being turtles all the way down.

What is really interesting to me is whether, being aware of the underlying nature of the universe, we're able to affect that outer domain from within. If not directly, than perhaps indirectly by means of a cosmic buffer overflow.

Of course, that assertion is just a metaphor. We may be "running" on top of a different layer of the universe, but that layer does not have to be separate from the universe. We would just define the universe as "a two dimensional information layer extruded into a three dimensional quantized space".

Re:Distance?

[JMZero]

The idea of the (reasonable) simulation argument is that not everything would be calculated out to the particle level all the time - the simulator would only figure that stuff out if there was some reason to. I mean, you can simulate the observable, macro-scale behavior of the sun without actually figuring out the position of every quark inside it.

But sometimes, like if some scientist is looking very close, you really do have to figure out exactly where every particle is in order to render that scientist's experience - and once you've done some of the particles, you have to store the value for the other ones too. Once they quit looking too closely, you just simulate the aggregate results. It's a tidy explanation of dual-slit type results and entanglement.

It's not, like, strong evidence or something, but it makes sense. And, while I can't think of a test, that doesn't mean a simulation hypothesis isn't testable. Under this view, these sorts of quantum effects are effectively simulation artifacts - and perhaps there's more dramatic artifacts that can be induced that would be more clear.

Re:Distance?

[Anonymous Coward]

If it involves string theory then it can support anything that you want.

Re:Distance?

[swillden]

The "simulated universe" "theory" is a joke. Real computers occupy 3 dimensions

At least, simulated real computers occupy 3 simulated dimensions.

Re:Distance?

[Kylon99]

Speaking about the simulation theory, if someone DID design this simulation, then they didn't really bother covering it up. Since the dual slit experiment shows it and it's, well, relatively simple to do.

Unlike the Matrix, no one bothered pulling wool over our eyes it seems.

Re:Distance?

[wonkey_monkey]

I mean, you can simulate the observable, macro-scale behavior of the sun without actually figuring out the position of every quark inside it.

So right now, "up there," there's a conversation going something along these lines...

"Dammit, my universe is running slow."
"Lemme look. Ah, there's your problem - it's the Dutch, poking particles again."

We're lucky we don't get rebooted when we fire up the LHC.

Or maybe we do...

Re:Distance?

[harryjohnston]

Entanglement IS communication, in the proper sense of the word. You cannot use it to send a message, but entanglement without hidden variables implies that information is exchanged between particles.

Only if you assume that particles actually exist in the first place, and that wavefunction collapse is objectively real. Neither of those assumptions is particularly well-founded.

Re:Distance?

[Anonymous Coward]

i will give it a try...

think of a video game. the distance you see between 2 objects in Call of Duty is not real, it is an artifact of the games software and emerges from the hardware/software running the game.

how the programmers programmed the game will determine how an object would interact. but the distance between 2 objects you see on the screen is not real. it is all just simulated in the computers hardware circuits.

in the holographic principle for the universe. essentially the universe is treated like an ultra detailed version of call of duty (complete with people shooting each other on occasion) we don't know what the internal structure of the universe is like (the computer hardware so to speak), we just know what we can see on the "screen". and that stuff on the screen follows a strict set of rules "physics".

spooky action at a distance is sort of like two adjacent bits in a ram chip flipping values at the same time. in the simulation those bits could appear very far away. but in the universes hardware...or in the computer game, they could be extremely close.

Re:Distance?

[Anonymous Coward]

Another possibility that would make the action at a distance non-spooky is the ER=EPR hypothesis:

Like initials carved in a tree, ER = EPR, as the new idea is known, is a shorthand that joins two ideas proposed by Einstein in 1935. One involved the paradox implied by what he called “spooky action at a distance” between quantum particles (the EPR paradox, named for its authors, Einstein, Boris Podolsky and Nathan Rosen). The other showed how two black holes could be connected through far reaches of space through “wormholes” (ER, for Einstein-Rosen bridges). At the time that Einstein put forth these ideas — and for most of the eight decades since — they were thought to be entirely unrelated.

But if ER = EPR is correct, the ideas aren’t disconnected — they’re two manifestations of the same thing. And this underlying connectedness would form the foundation of all space-time. Quantum entanglement — the action at a distance that so troubled Einstein — could be creating the “spatial connectivity” that “sews space together,” according to Leonard Susskind, a physicist at Stanford University and one of the idea’s main architects. Without these connections, all of space would “atomize,” according to Juan Maldacena, a physicist at the Institute for Advanced Study in Princeton, N.J., who developed the idea together with Susskind. “In other words, the solid and reliable structure of space-time is due to the ghostly features of entanglement,” he said. What’s more, ER = EPR has the potential to address how gravity fits together with quantum mechanics.

Re:Distance?

[ceoyoyo]

That's true. If the universe is a figment of my imagination, which is likely, then the particles do not need to communicate because their existence could not be other than I imagine it.

Re:Distance?

[Greyfox]

Oh yeah, and not even a very good simulation. Clearly corners were cut. The dodgy temporal consistency between various points, the hard coded speed limit, the way parts of it just crash when you put too much mass in one place. I'm pretty sure it's just an n-dimensional undergrad project to demonstrate how to convert hydrogen into plutonium with nothing more than a few simple rules. Of course, now that some plutonium has been created, they'll probably shut the whole thing down as soon as someone notices.

Re:Distance?

[Anonymous Coward]

Spooky action at a distance is only spooky if one assumes distance is real and not an emergent property of a projected/holographic universe.

Distance is only relevant while propagating. Since nothing is traveling there is no need to assume any such thing.

A related claim I find curious is the baseless assertion that anything "exists" in the human parlance at all.

Every known method of observation reduces to an expression of interaction. What we think of as "existing" or "real" is in fact describable exclusively as an "emergent" property of interaction. That people would find the existence of indeterminate states "spooky" at all is most interesting considering there is no evidence for the existence of determinate states.

In the same way in a computer simulation/game the distance between objects in no way represents the "distance" between them in the computers memory, perhaps our universe works at a similar level of abstraction.

Universe is a game written by clippy the paper clip after smoking too much "heap".

Re:Distance?

[harryjohnston]

Well, what I really meant was that our best current theory is a quantized field, so individual particles don't really have an independent objective existence but are just a subjective interpretation of certain kinds of vibrations. But your way works too. (At the end of the day it all boils down to how you choose to define words like "information" and "communication" so it's a bit of a tree-falling-in-a-forest thing.)

Re:Distance?

[Anonymous Coward]

I've always assumed that the "distance" was merely due to our observations in three-dimensional space, but quantum entangled particles are "touching" at some higher level dimension. It's a guess.

More likely a lower dimensional space. Don't forget about the weirdness that is the holographic principle.

Re:Distance?

[Anonymous Coward]

Meaningless if we can't prove that we wouldn't see it in a non-simulation.

Re:Distance?

[KGIII]

You're just a figment of my imagination and my psychiatrist (also a figment of my imagination) was right.

Re:Distance?

[KGIII]

Sure, first they say Pluto is not a planet and next they're going to say it's not the universe. I see where this is going...

Re:Distance?

[KGIII]

When I was young, and thought I was wise, I had a saying that I'd write all over the place - I'd stated it while tripping sack and it kind of stuck. Anyhow, I said, "Time is nothing but man's measurement for the passage of reality." I might have been right.

Re:Distance?

[locofungus]

Entanglement IS communication, in the proper sense of the word. You cannot use it to send a message, but entanglement without hidden variables implies that information is exchanged between particles.

Only if you assume that there are two particles while they're entangled. If there's only one particle then there is no communication between them. On measurement it changes from one to two particles.

One photon can go down both arms of an interferometer - one particle in two different places but the act of measuring it in one arm causes the part in the other arm to vanish.

An entangled pair of photons can go down both arms - detecting it in one arm causes the part in the other arm to appear.

Re:Distance?

[ultranova]

I see where this is going...

Well, don't keep us in excitement but emit your theory.

Re:Distance?

[Anonymous Coward]

maybe WE are a bug! maybe they did not intend for life to happen in this simulation.

Re:Distance?

[ultranova]

Entanglement IS communication, in the proper sense of the word. You cannot use it to send a message, but entanglement without hidden variables implies that information is exchanged between particles.

No, it doesn't. Any point in spacetime where entanglement can be detected is causally connected to the source of entangled particles through each particle's trajectory. This means information is not being transmitted from particle to particle but from the point of entanglement to the point of detection through multiple routes which interfere.

The problem arises from assuming unphysical observers who aren't themselves subject to quantum mechanics and can thus measure definite values. Observers who are will not measure a value but a quantum state - that is, the observer's quantum state will become correlated to the particle's. The first observation event doesn't reveal any information about the system, it simply reveals the gauge difference between the observer and a particular point in the system (or, equivalently, make the observer a part of the system).

Of course, the price of this is letting go of classical state entirely, except as an useful approximation in many circumstances, and accepting that you, yourself, are in a quantum state.

Re: Distance?

[master_p]

Which is very strong evidence that our universe is a simulation, running on a computer.

And the fact that reality isn't there until observed, is also a strong evidence of the universe being a simulation: the computer that runs it has limited resources, and so it optimizes rendering performance by not rendering what runs isolated and does not cause effects in its surroundings.

Re:Distance?

[Anonymous Coward]

I've always assumed that the "distance" was merely due to our observations in three-dimensional space, but quantum entangled particles are "touching" at some higher level dimension. It's a guess.

It's a crap guess. Most of those extra dimensions are very small. They don't stretch through an indefinitely large distance in 4D spacetime.

Re:Distance?

[JohnStock]

"What is really interesting to me is whether, being aware of the underlying nature of the universe, we're able to affect that outer domain from within. If not directly, than perhaps indirectly by means of a cosmic buffer overflow." This has interested me too. I've come to the conclusion that whoever creates a simulation allows for the conditions to reach a point where the evolved inhabitants become aware that they are in the simulation. But for what purpose? To migrate into the parent world.. ascendance, heaven...?

Re:Distance?

[JohnStock]

"I mean, you can simulate the observable, macro-scale behavior of the sun without actually figuring out the position of every quark inside it" This is not necessarily true. A very subtle change at the quark level could cause a systematic cascade that would affect the macroscopic world. This is how a nuclear explosion works (not quarks but a sub-atomic action triggering something on the large scale)

Re:Distance?

[Anonymous Coward]

What is a "real" universe? How would you ever know?

Re:Distance?

[JMZero]

So you simulate it at a lower level for a while to figure out the probability/frequency of that observable macro-level behavior, then just have it happen (on an observable scale) at an appropriate set of times. The whole observable world has to be at least somewhat consistent with the lowest level behavior, but that doesn't mean you have to simulate all those particles all the time.

Re:Distance?

[ceoyoyo]

It sounds like you're splitting hairs. Regardless of what a particle is, it's a measurable phenomenon. By any reasonable definition, quantum particles exist and exhibit behaviour we'd like to explain.

Re:Distance?

[Anonymous Coward]

People much smarter than you have been thinking about this for decades.". You assume too much.

Re:Distance?

[KGIII]

They're going to change the name and have a vote to say we no longer live in a universe because what's commonly accepted as a universe is now redefined and isn't going to quite match the new definition - and they'll probably do it just to be busy and appear to be productive. It will not actually change the nature of anything. It will have no value - not even in furthering the science.

But you knew that.

Re:Distance?

[harryjohnston]

We can already explain the behaviour of quantum particles, at least for all the kinds we know about.

Whatever. The only further point I think I should make at this stage is that science has assigned reasonably well-defined meanings to the words "communication" and "information", and by those definitions entanglement and quantum collapse don't qualify. Personally, I don't think the dictionary definitions are a good fit either, but that is arguably subject to interpretation.

In other words ( Score: +5, Transactionally )

[Anonymous Coward]

The two particles are actually ONE particle.

Yours In Peace,
K. Trout, Novosibirsk

P.S.: Re-elect Bill Clinton ( see the 22nd amendment ) !

Re:In other words ( Score: +5, Transactionally )

[U2xhc2hkb3QgU3Vja3M]

Damn. If only you had said "The three particles are actually ONE particle" you could have started a huge God-related trolling thread.

Re:In other words ( Score: +5, Transactionally )

[Anonymous Coward]

Well, neutrons are made of three quarks. Something like 'The Blue and the Green and the Ruby Red' then?. If they eject a beta particle, that particle can never return home again - it is banished from the center of all. When this happens, an Atom is born along with the dichotomy of positive and negative.

Re:In other words ( Score: +5, Transactionally )

[KGIII]

It's like rain - on your wedding day!

Isn't it ionic, don't you think?

This Just In!

[thedonger]

Quantum theorists prove quantum theory. Say it only works when you aren't looking! Story at 11 -- but only if you observe it.

Practical applications will exist when people stop looking for them.

Duke Lacrosse team accused of quantum rape. Local woman says they "entangled" her from miles away. Rape kit both confirms and refutes claims, depending on who's observing it.

Re:This Just In!

[Locke2005]

This just in: Schrödinger's cat found dead!

Re:This Just In!

[Anonymous Coward]

"Rape kit contained dead cat. Would not recommend."

Classics IV

[turkeydance]

Spooky

Don't

[Anonymous Coward]

Shhh, don't observe it, or you will crash the simulation. And then we are all gone... I'm telling you ... gone! Your friends - gone; your wife - gone; you - gone! Don't crash the simulation white it is paging, we must not become aware of it.

Expert reactions

[Anonymous Coward]

http://www.sciencemediacentre.org/expert-reaction-to-results-from-the-loophole-free-bell-test/

Instantaneous quantum communication networks I suppose is one thing we may take away from this...

Re:Expert reactions

[tnk1]

This does not permit actual communication. Communication would require that information be transmitted from one end to the other.

Knowing that the state that you observe is also appearing inverted on another particle somewhere else doesn't help you because the state of the particle is random until you observe it. Therefore, while both sides understand that they are viewing the inverse of the other particle,

1. Since, the value observed is random you can't choose what it will be ahead of time. That prevents you from having a protocol to send information.
2. Also, as a consequence, there is no way of knowing if the particle was previously observed by the other side, or for the first time by your side
3. Therefore, you not only don't know what the content of the message is, you don't even know that the person on the other side has even tried to send a message.
4. All you can be sure of is that, if and when the other side looks at their particle, it will have the expected value.

That does have uses, it just does not have uses for communication.

Someone else mentioned "perfect" encryption as one use, since you don't have to worry about sending a one-time key insecurely to your correspondent, you just observe your particle and the other side instantly knows what the sending key was without the possibility of it being intercepted in transit.

However, the information about what particle you chose and the message itself still have to arrive via light speed or slower means.

Re:Expert reactions

[Anonymous Coward]

An interesting application would be synchronizing decisions unpredictably, especially in military usage. You agree on an algorithm to choose the details of a strategy, and then feed the state of the quantum system at a certain point.

It will be random but both participants have the same result and thus knows what the other will do, without any chance of interception of the plan.

FTL information exchange

[Anonymous Coward]

The distance [...] ensured that information could not be exchanged by conventional means within the time it takes to do the measurement.

This connotes that information is exchanged by non-conventional means, and instantaneously. THAT IS WRONG.

Information DOES NOT get exchanged faster than light! NEVER.

Why can't a journalist write proper stories?

Re:FTL information exchange

[Anonymous Coward]

Nobody has ever said it was 'wrong' but that it's impossible to control.

However, some have argued that superluminal communication can be done through quantum entanglement:

“Hensen et al. have performed an outstanding experiment, requiring an impressive level of expertise, simultaneously closing booth loopholes for the first time, and once again confirming that quantum mechanics is weird in a way that we could not imagine if the theory hadn’t predicted it.

“The techniques used in this experiment are highly relevant to the growing research effort in quantum technologies. In particular, they help pave the way for distributing entangled states and implementing wide area networks for quantum communication.”

-Dr Anthony Lain, Research Fellow, University of Bristol

Re:FTL information exchange

[sexconker]

It's because they're stupid, that's why. That's why everybody does everything.

-Homer Simpson

Re:FTL information exchange

[U2xhc2hkb3QgU3Vja3M]

But what if our knowledge about the speed of light is wrong?

Re:FTL information exchange

[Anonymous Coward]

Your entangled pair would still need to travel to their respective points of measurement at sub-luminal speeds thanks to that killjoy Einstein.

Re:FTL information exchange

[Anonymous Coward]

but if time can be observed moving both forward and backward, what is the per seconds part of the speed of light value? time has been shown to not be static in this observation, so 1 second could be observed in 100 seconds or .001 seconds... so what is the observed time dimension for the speed of light?

Re:FTL information exchange

[ceoyoyo]

Information IS exchanged. Absent a hidden variable that is carried along with both entangled particles, they have to communicate their state when observed. We cannot use that process to communicate arbitrary information of our choosing faster than light.

Re:FTL information exchange

[slew]

but if time can be observed moving both forward and backward, what is the per seconds part of the speed of light value? time has been shown to not be static in this observation, so 1 second could be observed in 100 seconds or .001 seconds... so what is the observed time dimension for the speed of light?

The problem with your question is that you are assuming that time is the same in frames of reference that are moving relative to each other. The short answer is they are not. Take this example from special relativity...

You are in a car driving to run-over an enemy watched by your friend on a nearby grassy knoll. You turn on your headlights and light from your headlights goes forward "at the speed of light" to illuminate your enemy and see his eyes illuminated as you race forward at 100km/h. Your friend on the grassy knoll is not moving at all and sees the light apparently travel at the "speed of light" from your car even though he is stationary. At first, you might think that your friend must see the light going "at the speed of light + 100km/h". However, he measured it and confirms it travelling at the only speed of light (not +100km/h). What gives?

Is the distance wrong, or the time wrong? In special relativity, you can treat things as if time dilated, or space contracted, but general relativity (e.g., when you take in consideration acceleration instead of constant velocities) actually suggests that both happen.

The wacky thing about this is that from the point of view of a photon (which is always travelling at the speed of light), there effectively isn't any distance at all to travel (it effectively exists at all points on its world line simultaneously), even though it is only travelling at the speed of light relative to other observers.

ESP/Clairvoyance are really quantum interactions..

[Anonymous Coward]

The thing is, if time is an illusion, and distance is an illusion, then things like ESP, Clarivoyance, specific aspects of dreams (locations, music) that come true, deja vu, etc may simply be really quantum 'blips'

Absolutely no way to prove it (at least not yet, maybe when we get implanted memory/thought recorders with timestamps...). but if I had a dollar for every time I thought about someone mere minutes/seconds before being texted/called by that same person (even people I rarely communicate with) I'd have enough for nice new Infiniti.

Physicists correct me if I'm wrong.

[trout007]

I thought all this means is that you can entangle two particles when they are close. Basically this means all you know is one is + and one is -. Then if you separate them and measure one you know what the other one is. That doesn't seem so spooky.

Re:Physicists correct me if I'm wrong.

[ceoyoyo]

You've essentially described a hidden variable theory (the particle is + or -, you just can't see it). This guy named Bell proved that if that's the way the universe actually works then it implies some even spookier things.

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

Re:Physicists correct me if I'm wrong.

[Anonymous Coward]

There is a machine called a Stern-Gerlach apparatus that, for example, can rotate the state to some other pair, say u and d. So you send in a +, and it has a 50% chance of becoming u, and a 50% chance of becoming d.

Here is the spooky part you take the entangled + and - and separate them by a large distance. Then you run the + through the machine. Let's say it comes out d. When you run the other particle through the machine, it will come out u.

Re:Physicists correct me if I'm wrong.

[slew]

I thought all this means is that you can entangle two particles when they are close. Basically this means all you know is one is + and one is -. Then if you separate them and measure one you know what the other one is. That doesn't seem so spooky.

That's only the "non-QM" entanglement. The spooky part of the problem occurs when the particles are entangled in a superposition of states.

The difficulty is that it's hard to describe a non-QM analogy of an object in superposition of states (e.g., cat-is-half-dead). The so called QM bomb tester thought experiment is perhaps one of the easier way to understand how QM superposition might be different that simply an emergent property of an unknown or hidden underlying probability distribution function. Given a basic understanding of superposition, the idea entanglement and observed correlated wavefunction collapse/measurement might be a bit spooky (if observed correlations are in particles that are farther apart than light can travel during the time window of the observation).

Re:Physicists correct me if I'm wrong.

[LesFerg]

How is that a hidden variable theory?
Its much the same as taking two balls of silly putty and pressing them against opposite sides of a coin. In a dark room. Then taking one of them down the road to your mates place, where he can look at it and know what the one you left at home looks like. Whats hidden? Its only the imaginary "I don't know" probability wave which you "collapse" by looking at one of them. All the rest is just a big mind-fuck. And Einstein was more concerned with the stupid theories people were making up about quantum physics than the challenge of broken locality.

Re:Physicists correct me if I'm wrong.

[Anonymous Coward]

Bell's theorem does not prove anything. It is a mathematical proof of a portion of a field theory which is not understood and we have little empirical evidence for. A cart before the horse scenario in the same vein as classical non-relativist physicists used to dismiss Einstein a century ago. In well-educated physics circles Bell's theorem loses its glamour and showstopping appeal. Just don't tell the math department that ;)

Re:Physicists correct me if I'm wrong.

[Anonymous Coward]

It is spooky - the entire universe has conspired to keep one as + and the other as -.
Some machinery is at work.
In a car, if you turn the left indicator on, the right indicator is off. And vice versa. Certainty nearing 100%.
But there is underlying machinery in the car for ensuring that happens.
So what is the underlying machinery that conspires one to be + and other to be - even though there
is separation of several kilometers between them?
And even more rude question, what kind of connected machinery does it take to prevent us from modulating or forcing one end to be - so that other end is + and thus effectively prevent FTL communications?

Re: Physicists correct me if I'm wrong.

[holmstar]

The impression in the putty is a hidden variable.

Re:Physicists correct me if I'm wrong.

[Anonymous Coward]

It is indeed a hidden variable theory.

He is saying the particles met and decided on their outcome. They then represented that outcome as any set of variables stored in the particle. The particles then cannot communicate before both particles are measured and then the results compared. The fact that the state of each particle is local to that particle is what makes it a hidden variable theory.

Bell proved that QM cannot be explained by a hidden variable theory. Read ceoyoyo's link, he is correct.

Re:Physicists correct me if I'm wrong.

[Anonymous Coward]

It doesn't work like that as Bell's Inequality is designed to prove. Your silly putty has a definite state from the get-go, but entangled particles are neither + nor - until you observe them. What that means is that, at the moment they are created and entangled, the particles are NOT imparted with any information about whether they are distinctly + or - (they are actually a superposition of both states). That information literally doesn't exist until the particle is observed, and its entangled partner instantly assumes the inverse state. It's not that each particle has a hidden piece of information somewhere (the hidden variable) that only surfaces when observed, it's that decision about which one is + or - is not made until the instant the particle is observed.

That's the theory anyway, but it stands to reason that SOMETHING somewhere in the universe (or beyond) is deciding what state the particle will be when it's observed, be it the wavefunction or some other unknown mechanism beyond our knowledge, or just randomness.

Re:Physicists correct me if I'm wrong.

[ceoyoyo]

The impression on the silly putty is "hidden." Quantum particles appear to exist in a superposition of states. In some sense, they exist simultaneously in every possible state. When they interact with another system that's big enough (they're "observed") they behave as if they were in only one possible state. A "hidden variables" theory postulates that the quantum particle was really in that state all along, you just couldn't see it (it was hidden).

The hidden variables explanation is very compelling, because it seems so obvious. The problem is, it doesn't really agree with observations, and Bell's inequality suggests that if it is true, even weirder things are also true.

In this experiment, for example, two electrons were created in two different labs. There wasn't any pressing of silly putty, they were completely independent. These electrons were then caused to emit a photon each. Those photons were sent to a third lab and entangled. And the consequences of that entanglement were then observed in the *original* electrons.

Re:Physicists correct me if I'm wrong.

[Anonymous Coward]

INAP, but in the + / - particle example, until one of the particles is measured, both particles are actually both + and - (i.e. the cat is alive and dead). To say that one of the particles has a definite value, that we just don't know yet, is the hidden variables part I think. The problem with that is that there can only be hidden variables only if they are non-local (something like de Broglie/Bohm theory).

Re:Physicists correct me if I'm wrong.

[Anonymous Coward]

That's indeed a simple non-spooky case. The easiest example of spookyness is when you have not just up/down as a property, but also left/right, and you can only measure one of the two properties. In that case, you have two possible outcomes depending on whether the two distant observers both measured the same direction or not. Do you have one ot two hidden variables? A hidden variable theory states that the (number of) hidden variables must be set when the entangled pair is created. That number cannot depend on the future actions of two distant observers.

Re:Physicists correct me if I'm wrong.

[Anonymous Coward]

this this this this this this this

please please please mod parent up

Change it twice

[Anonymous Coward]

I'm not versed at all in entanglement and quantum mechanics, but each time I go read upon it I end up with this:

1. Create two entangled particles: P1, P2
2. Send P2 somewhere remote
3. Measure P1 get X
4. Determine that when P2 is measured it will result in ~X or something.

And that's it. I haven't encountered anything that says "Change P1 and P2 changes too" except in speculation and headlines. If my description above is right, then it's "split a pea in two, and if you measure the first half, you'll know that the other half will be a hemisphere with opposite orientation" which isn't too useful.

Re: Change it twice

[Anonymous Coward]

This.

Why isn't it possible that the spin of the entangled electrons is fixed at entanglement setup time - and when they are observed separately, we naturally measure up-spin (1) on one side and down-spin (0) on the other side?

No wave function "collapse", no "observer effect", no "Copenhagen school" is needed to explain that: plain classical physics.

Re:Change it twice

[ceoyoyo]

Did you read the article? It gives a pretty good description of the experiment.

They create two electrons, A and B, completely independently, in two different, widely separated labs. They use those electrons to produce a photon each (Ap and Bp), and send those photons to a third lab. The properties of the photons will depend on the properties of the electrons, but the electrons were created independently so the properties of the photons should not be correlated with each other. In fact, if at this stage you test the electrons and photons, you find that A and B and Ap and Bp are not correlated.

That third lab entangles the photons. Then the two original labs test their electrons. Now they discover that the properties of A and B ARE correlated.

Re: Change it twice

[Anonymous Coward]

I'm also not an expert, but as far as I understand it, that's the "Hidden Variables" theory that Einstein had hoped was true.

Unfortunately, Bell's Inequality shows that the hidden variables theory doesn't work.

Re: Change it twice

[Anonymous Coward]

So what if the universe follows deterministic bohmian mechanics:

https://en.m.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory

where the apparent "randomness" of small particles and interference in a double slit experiment is an emergent property of small ripples in the "pilot wave":

https://youtu.be/nmC0ygr08tE ... which, if you posit that the bohmian pilot wave propagates at the speed of light across spacetime, is far more intuitive than magic spooky action at distance.

Every quantum mechanical phenomenon can be explained via bohmian mechanics.

Re: Change it twice

[Anonymous Coward]

But what if the universe follows deterministic bohmian mechanics:

Wikipedia article about Bohm's interpretation of quantum mechanics

... where the apparent "randomness" of small particles and interference in a double slit experiment is an emergent property of small ripples in the "pilot wave":

Video of bohmian pilot waves.

... which, if you posit that the bohmian pilot wave propagates at the speed of light across spacetime, is far more intuitive than magic spooky action at distance.

Every quantum mechanical phenomenon can be explained via bohmian mechanics.

Re:Change it twice

[harryjohnston]

If I'm reading the paper correctly, that's because the results of each experimental run are discarded unless the measurements of Ap and Bp show that A and B are correctly lined up with one another. (Or the experiment isn't performed until the measurements show that A and B are correctly lined up with one another, it isn't entirely clear.)

The Economist article, unsurprisingly, kind of skimmed over that part. :-)

To extend the pea analogy, Alice and Bob both have a half-pea, oriented at random. They both tell Carol which way their half-pea is facing, and if they aren't lined up, Carol tells them to try again. When you're done, the alignment of the two half-peas is definitely correlated, but that doesn't mean that the two half-peas were talking to one another..

Re: Change it twice

[harryjohnston]

It's a much more complicated theory, with no obvious advantages, so Occam's razor suggests that we shouldn't get too excited about it.

Also, you can't posit that the pilot wave propagates at the speed of light, because it doesn't propagate through space at all. As per the article: "In de Broglie–Bohm theory, the velocities of the particles are given by the wavefunction, which exists in a 3N-dimensional configuration space, where N corresponds to the number of particles in the system."

Re: Change it twice

[harryjohnston]

In short, it is because the nature of spin itself is non-classical. Whenever you look at the electrons, they are always either pointing either up or down - never left or right, because there isn't any such thing.

The way in which the is-it-up-or-is-it-down property transforms as you look at the electron from different angles makes it impossible for the spin to be predetermined for more than one angle at a time. If measuring it at one angle would definitely produce a spin-up result, the result of measuring it at any different angle has to be uncertain.

Re:Change it twice

[Anonymous Coward]

Which is trivially explained as the measurement actions entangling the lab with the experiment and resulting in various levels of decoherence. No need for retro-causality.

No

[aepervius]

"Does this mean faster than light communication is actually possible?"

Nope. See no communication theorem. Basically you cannot communicate *any* information whatsoever.

More news

[DrYak]

This just in: Schrödinger's cat found dead!

Onlooker confirms cat actually alive!

Re:More news

[sconeu]

https://www.youtube.com/watch?...

Or, in other words...

[DrYak]

And that's it. I haven't encountered anything that says "Change P1 and P2 changes too" except in speculation and headlines.

Yup. Indeed. Quantum entanglement CANNOT be used for faster-than-life communication.

If my description above is right, then it's "split a pea in two, and if you measure the first half, you'll know that the other half will be a hemisphere with opposite orientation" which isn't too useful.

(with the subtle difference that the real quantum pea isn't actually split in advance. You end-up with a have only the moment you look at it, until that moment both half of the quantum pea exists with 0.5 distribution at both P1 and P2 places)

But basically yes "you'll know that the other half will be a hemisphere with opposite orientation" is a decent simplified explanation of why you can't use it directly for faster-than-light communication.

(But can use it for secure password communication in quantum cryptography).

Re:ESP/Clairvoyance are really quantum interaction

[Anonymous Coward]

if I had a dollar for every time I thought about someone mere minutes/seconds before being texted/called by that same person (even people I rarely communicate with) I'd have enough for nice new Infiniti.

A "nice" Infinity costs at least $37,000.

Assuming a convenient (though not unreasonable) 34 years of being texted/called by people, you are claiming this happens to you on average of three times a day?

So three times a day, consistently, you think of someone minutes/seconds before they call you?

I suspect it is far more likely that you just remember these occasions far better than the cases where someone calls you randomly, specifically because they are not the norm.

Zero lag means no need to send humans to Mars

[dsmatthews9379]

Why send humans to Mars now if it looks like we will have communications links with zero lag time? NASA should be able to control humanoid robots remotely over any distance with the human operator experiencing the sensor data sent back in real-time. Perhaps not "right now" but certainly by the time they can organise to get humans to Mars, and back. It seems that science is moving faster than science fiction and "The Martian" movie is nothing more than a romantic fantasy for "big boys".

Re:Zero lag means no need to send humans to Mars

[ledow]

Because the science might be right but the engineering is still extremely far away.

We might be able to entangle two particles in an lab experiment and test them at distance, doing so as a matter of routine with enough particles to form a reliable communication channel across millions of km's with inch-wide precision with something that you can put into a craft? That's still just science fiction. And any mission you launch will still take years to bring that technology to even Mars, let alone anywhere else.

Honestly, it's like saying we've invented a battery, why don't we just light up the entire planet right now? It takes at least decades and more likely hundreds of years of engineering to fill that gap.

And then you'll find that it's not all that useful compared to, say, sending radio communications.

Though you can entangle photons/particles in theory, there is STILL not way to send information using that faster than the speed of light. It's as simple as that. And that's still an 8-minute delay to the Sun at the very least, and stupendous delays if you try to go out towards the outskirts of the solar system.

Fortunately, the people in charge of such things are physicists and engineers and not random commentors on Slashdot.

Re:Zero lag means no need to send humans to Mars

[Anonymous Coward]

Because quantum mechanics / relativity says the exact opposite. It is nearly certain we will never have communications with zero lag time. This would imply all sorts of paradoxes that wouldn't jibe well with what we currently observe.

This "spooky action at a distance" involves two particles behaving the same way, even when separated by a distance. It cannot be used for communication for reasons explained in numerous other posts.

It's kinda like this:
A) I take two pictures...one of each side of a coin (entangle two particles)
B) I send 1 picture to Bob, and 1 to Alice (separate the particles)
C) Bob looks at his picture & sees heads. He "instantaneously" knows that Alice's picture shows tails.

The above cannot be used for communication.

Note: the above is a simplification...quantum particles are considerably weirder

Re:Zero lag means no need to send humans to Mars

[tomhath]

The same can be said about sending people to Mars

Intelligent Teasing

[Tablizer]

Quantum Mechanics is a Great Tease.

At first it looks like you can do wonderful things, like send messages faster than light or travel back in time. BUT when you look at the details or actually try it, there's always a catch that limits the usefulness.

Me thinks Quantum Mechanics was designed by Oracle lawyers: it looks like you got a great big powerful database...until you go to use it and find out the contract does something ridiculous like count "transaction" as each table cell read, NOT per query, filling your license quota the first week*.

Reminds me of a joke:

Q: "What's the difference between Larry Ellison and God?"

A: "God doesn't think he's Larry Ellison."

Maybe he does.

* Hypothetical example only based on patterns of more complex actual examples. Don't sue my tail off.

Faster than Light Travel

[Dareth]

You just need someone to see you are there, and poof, you are there. No travel needed at all.

Re:Faster than Light Travel

[Anonymous Coward]

What guarantees that all your particles end up the same relative position to each other? It doesn't really help if one of your arms ends up in a different galaxy (with all of its atoms homogenously spread out there).

Re:Faster than Light Travel

[Dareth]

You just have to hope whomever sees you there has good vision. ;)

Retrocausality

[Anonymous Coward]

The economist article is obviously a message from the future because it's dated the 24th.

Observers irrelevant, no wave function collapse

[Theovon]

Wave functions don't collapse. They just evolve with time. A state of superposition is equivalent to oscillating between states in a reversible way. Some interactions lead to state changes that are functionally irreversible because changing back to an earlier state becomes exceedingly impossible. For instance emitting a real photon.

As for observers this is just an interaction like any other. The observing particle becomes entangled with and interacts irreversibly with the observed. There is nothing special about conscious observers. Any irreversible interaction is an observation.

Sounds pretty useful for cryptography to me

[Phil Urich]

Use it for what? It's a random string of binary digits. I guess you'd know exactly what the random string of binary digits was on the other end. However that is not useful information.

Since you could have a pair of random and shifting strings that nonetheless stayed in sync with eachother, well, that seems like with a bit of effort it could be pretty damn great for certain cryptographic uses.

Re:Sounds pretty useful for cryptography to me

[JohnStock]

It's already been mentioned further up this branch that it's useful for cryptography. The most recent point is that it's useless for sending information.

Re:Sounds pretty useful for cryptography to me

[Anonymous Coward]

except it doesn't propagate at the same speed as the message...

Now I get it.

[Anonymous Coward]

It all makes sense! There is no big bang. As an observer we are actually watching the universe in reverse from inside a black hole.

reverse time?

[Reisrdok]

Maybe time runs backwards for them, maybe all particles were in sync in the beginning (end from our perspective), and collision just throws them out of sync? Just woke up..

Re:reverse time?

[Reisrdok]

..Which would mean that time actually runs backwards for us. And communication over quantum entanglement is impossible, because we are just witnessing events that have already happened. And yes, I have no idea what I am talking about.

Another flawed experiment

[Anonymous Coward]

This is a dupe BTW, we had this earlier in the year.

Basically they shoot Photo A through Electron A, and Photon B through Electron B.
"Entangle" the two photons, which in practice means an interaction followed by filtering photons whose spin angle is different. If its the same let it through. Different then its not entangled and the result is ignored.

Now check the spin of electron A.
By *Spooky* distance effect, the spin of electron B is set to be the same.

Now go look at the "entanglement" check. If Electron A was spinning differently than Electron B, the result would be discarded as 'non-entangled' photons! So yet again we have a simple scam.

"Yet a number of loopholes remained—ways that hidden variables might exert some influence, though the purported mechanisms became increasingly contrived as years and experimental finesse advanced"

What fucking hidden variables, EVERY SINGLE Quantum entanglement experiment contains the coincidence detector, or similar filtering. It's not hidden variable, the experimenter is the extra variable!

Re:Another flawed experiment

[Zero__Kelvin]

But what happens to Alice and Bob?

Re:Another flawed experiment

[Anonymous Coward]

Not to mention Carol and Ted...

Disguised fraud

[Anonymous Coward]

Electron X produces Photon X.
Electron Y produces Photon Y.

Both electrons are far away by miles.

Photon X is "entangled" with Photon Y

Electron X's spin is tested, by 'spooky distance effect though the entangled Photons' Electrons Y spin is also set to be the same.

What's actually happening?

There is no way to entangle two photons, actually what happens is you test to see if they have the same spin (not what the spin is, only if its the same in both) and then declare it entangled, and only considered the corresponding result for those photons.

In other words, "will this result prove my experiment yes/no? If yes then measure electrons to prove my experiment"

You can see this in all Quamtum entanglement experiments. e.g. Quantum Eraser:

https://en.wikipedia.org/wiki/Quantum_eraser_experiment
"Both detectors are connected to a coincidence circuit, ensuring that only entangled photon pairs are counted. "

Its filtering, if the electrons had different spins then the photons would fail the "entangled" test and the result would be ignored.

Bells is also not correctly applied, since its applied to the subset of photons declared as 'entangled'.

If you strip off all the obfuscation its a lot easier to see the scam here.

It's still a sensitive system

[ceview]

These kinds of experiments don't really say much about how large scale matter behaves in real world applications. It might have applications in quantum computing but these things are statistical or probability effects that easily collapse. This is important because you still can't send a 'coherent' message faster than light. The signal to noise ratio ends up making the result to noisy to get a signal.

Are electrons measured before being entangled?

[master_p]

If not, then here is your experiment flaw.

It may be that the correlation exists due to the time the electrons are fired. I.e. when two electrons are fired at the same time, then there spins might be corellated.

By same time, I mean the same light cone, as defined by GR.

If particles are fired in different time cones and then we find out they are not correlated, then it means that correlation is somehow linked to the frame of reference.

Anothet possible explanation is that entangling two photons creates some gravity waves that travel through the connected wires backwards to the electrons, affecting their spin.

Entanglement communicating through time

[JohnStock]

Could it be that entangled particles could be communicating to each other forward in time, that way we perceive the action as FTL and it does not break any rules?

Removing predetermined randomness

[JohnStock]

"A potential weakness of the experiment, he suggested, is that an electronic system the researchers used to add randomness to their measurement may in fact be predetermined in some subtle way that is not easily detectable, meaning that the outcome might still be predetermined as Einstein believed." "To attempt to overcome this weakness and close what they believe is a final loophole, the National Science Foundation has financed a group of physicists led by Dr. Kaiser and Alan H. Guth, also at M.I.T., to attempt an experiment that will have a better chance of ensuring the complete independence of the measurement detectors by gathering light from distant objects on different sides of the galaxy next year, and then going a step further by capturing the light from objects known as quasars near the edge of the universe in 2017 and 2018" If the universe if predetermined, then this wont help one jot and is no less predetermined by the electronic system used in this experiment. Smells like those NSF trying to jump on the bandwagon to me.

Re:ESP/Clairvoyance are really quantum interaction

[Anonymous Coward]

Perhaps a bit much, but you can still get a nice 2010 for 18k.

But yes, it happened twice yesterday. My wife facebooked me just a few seconds after I thought about her (of course I think about my wife a lot so nothing definitive there) and then I got an email from a co-worker from another department that I wasn't expecting contact from, about 2 minutes before I was thinking about a joke he had said at the last company meeting.

We have the phrases "I was just thinking about you" or "speak of the devil.." because we often come across these seemingly coincidental situations pretty often. Perhaps it's just a smidge more than coincidence?

Re:ESP/Clairvoyance are really quantum interaction

[Anonymous Coward]

If you compare that number with the number of times you thought of someone and weren't called by that same someone you would notice it's infinitesimally small. It only seems significant because you just never notice the other billions and billions of instances where it didn't occur.

Quantum Theory Experements

[perih60]

if one spends more and more resources , looking for , i shall use this as an example " something extinct " one can look forever ! how many of you have read the FEYNMAN lectures ? for you to make up your mind about me , you need to know i have no formal education , but for work in kind , have had private lessons from 3 Prof. , and a lot of employers i respect , the choice is in your hands

chicken egg paradox

[perih60]

i can see no paradox , did not life start thru evolution ? if yes then obviously the egg in the form of a first cell . i'm still deciding about god , however i read on this site that the Pope stated evolution is real .

Are you high?

[Anonymous Coward]

and time runs backward as well as forward

Are you high?

chicken and egg problem

[perih60]

are not both the chicken and egg products of evolution ? so starting at the beginning , the chicken would have to be the result of single cell at the start of evolution !