Quantum Teleportation Achieved Over 7km of Cable (sciencealert.com)

I Think this article might be a bit misleading.. by Anonymous Coward · 2016-09-20 22:09 · Score: 5, Informative

Someone explained this news to me recently, they said the scientists didn't send ~information~ over quantum entanglement, they sent the data across normal networking means and sent and a key to unlock the data via quantum entanglement. The method used has deep implications for security and encryption methods, but not faster than light data transfer. Just wanted to clear that up.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-20 22:10 · Score: 5, Funny

No. This article clearly means we'll be transporting ourselves to Mars before the week is out.

Quantum encryption not communication by jellomizer · 2016-09-20 22:13 · Score: 1, Offtopic

The data is being send the traditional way. But the information is encrypted by the entangled particles then decrypted by its partner.
The real trick is to acutely time the communication delay and cache up the states of those times.

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Re:Quantum encryption not communication by Anonymous Coward · 2016-09-20 22:55 · Score: 0

The real trick is to acutely time the communication delay and cache up the states of those times.
That sentence makes no sense.
Re:Quantum encryption not communication by Big+Hairy+Ian · 2016-09-20 23:55 · Score: 1

And also wtf has this got to do with Teleportation?

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Re:Quantum encryption not communication by Anonymous Coward · 2016-09-21 00:25 · Score: 1

"Quantum teleportation is a process by which quantum information (e.g. the exact state of an atom or photon) can be transmitted (exactly, in principle) from one location to another, with the help of classical communication and previously shared quantum entanglement between the sending and receiving location."
https://en.wikipedia.org/wiki/Quantum_teleportation
Re:Quantum encryption not communication by Anonymous Coward · 2016-09-21 01:16 · Score: 0

Word Salad.

Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-20 22:17 · Score: 1

I know there's a black and a white ball in a box. I pick one of them without looking at it and transport it 10km away, then I check what colour it is. Now I also know the colour of the other ball, but is it fair to say that checking the colour "affected" the ball I left in the box over the distance of 10km? Obviously it's absurd. Why would quantum entaglement be any more mysterious than this?

Re:Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-20 22:49 · Score: 4, Informative

That's not quite the trick.
You have a box with black and white balls. You take two, X and Y. You throw X without looking at it to Bob. "Hey Bob what's the color of your ball?", Bob says its black. You open your hand and look at your ball,..... amazingly it's black too. No matter what color Bob says, yours is linked to his color!
The claim: The act of Bob looking at the color *sets* the color of his ball, and because they are linked by a mysterious spooky distance effect, it also sets the color of your ball. The balls normally have no color.
The reality: You take a photograph of the balls. You throw one, Bob looks at his, you look at yours. The photograph is checked to see if it the balls have the same color? Yes? Then you count the experiment. No? Then you discard the experiment as a failed entanglement.
EVERY entanglement experiment includes this filtering stage. Since the information on whether the entanglement was a 'success' or 'not' is sent along another line, it follows that you cannot use this "faster than light" communication until the fixup information arrives via normal communications.
Bob does not know if his ball is a valid entanglement until details of the outcome of the photograph are sent to him.
For the purposes of this experiment, we downplay the photograph, and we never count the photograph as a "detection". When the ball is measure by Bobs eyes, we count that as a detection, when the ball is photographed, we don't count that as a detection until someone looks at the photograph. I kid you not.
Re:Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-20 23:00 · Score: 0

So... Alice picks up two balls without looking and throws one to Bob. Alice then asks Bob what his ball's colour is. If he says "black" and Alice's ball is also black then it's a successful entanglement. If Alice's ball is white though, they discard this instance of the experiment as a failed entanglement. Did I get that right? :)
Re:Quantum Entaglement is not strange at all by wonkey_monkey · 2016-09-20 23:11 · Score: 3, Insightful

Not really, but if you want a completely descriptive analogy for quantum entanglement... well, there isn't one.
Alice and Bob have two different ways of measuring particles, and each way can give two different results. They might do a "brightness" measurement (analogy) which returns either black or white. Or they might do a "colour" measurement, which returns either red or blue.
The trick is that, although you might think the results are predetermind, and therefore fixed, they're not. If Alice does a brightness measurement and Bob does a colour measurement, there is now no way for Alice to get a colour measurement that will definitely match Bob's. The information is gone. It might match by chance, but it equally might not.
So Alice and Bob measure at random - sometimes brightness, sometimes colour. Later they compare notes on which tests they made on which photons (they can do this in public), and discard any results where they didn't use the same test. The remaining results are what they use to make up their key - a 0 for black-or-red, a 1 for white-or-blue.
If they do a test encrypt, and find that it doesn't work, that indicates someone else was intercepting their photons and screwing up the entanglement (because that person would have no way of knowing whether to test for brightness or colour).
At least, that's my understanding. I could be wrong, and probably am.

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Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-20 23:31 · Score: 1

Alice has Bob by the balls. This is the only thing that really matters.
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-20 23:54 · Score: 0

Somewhat true, but you can get the error rate to be below that of what chance would suggest for grabbing two random colors. If you grabbed two random colors from a mix of colors and saw you failed to get a matching pair 50 percent of time, nothing special happened. When you can do it consistently right more than 50 percent, e.g. 90 percent or way more in some entanglement setups, then you have something much more special than just a classically random color ball hidden in an envelope. Hence Bell's inequilibrium showing quantumechanics involves more than just locally hidden classical info...
Re:Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-20 23:59 · Score: 0

" they discard this instance of the experiment as a failed entanglement. Did I get that right? :)"
Not quite so blatant. They select the subset of balls that are connected by a different means. But once you know you have the two related balls, the other related properties can be inferred.
So for example, take a real 'proof' experiment, Quantum Eraser:
https://en.wikipedia.org/wiki/Quantum_eraser_experiment
1. Photon X is split into X1 and X2 by interacting with a crystal which creates two lower energy but otherwise identical photons.
2. X1 is further split int X1a and X1b and these go into the double slit experiment, to create interference fringes.
3. So far so good, how many photons are detected is totted up, and sure enough peaks have more photons, troughs have fewer photons.
4. Now a vertical polarizer is put in from of slit X1a and a horizontal one in from of X1b... now no fringes are detected. Photons are detected but that's just noise from background, there is no statistically significant peaks and troughs.
5. To pass both the horizontal and vertical polarizers, it would have to be a 45 degree polarized light, only that has equal components in vertical and horizontal to create our fringes. That would be a very very rare thing.
6. Remember X2? We split it off earlier. It goes into another detector, and we are actually only counting photons detected when detector X2 fires AND the detector at our fringes fire. This is how we filter the bulk of the noisy photons. Without this we get a lot more noise photons. It is called a 'coincidence circuit'.
7. So we put a 45 degree polarizer in front of detector X2. Now X2 only detects 45 degree photons.
8. By spooky distance effect, we can detect interference fringes again with statistical significance.
The claim:
By forcing all X2's detected to be at 45 degrees, we are forcing X1a to be at 45 degrees and X1b at 45 degrees, which is why we can now detect fringes. The act of detecting it at X2 causes an effect to ripple back in time, back to when X2 was split from X1, so now X1, and X1a and X1b also have that 45 degree polarization.
Only the first detection *sets* this property, later detection only repeat the first. So for example, we don't count the interaction with atoms in step 1 as a detection, because... well.... just shut-up ok!
The reality:
If X2 doesn't detect anything we ignore all the other photons, so all we've done is now filter for only photons with 45 degree polarization. We know that the X2 photon *had* 45 degree polarization, and thus X1, and X1a and X1b also had that polarization. Since we only consider photons when X2 detects something, we are filtering out all the noise to reveal the signal created by 45 degree polarized photons.
No special magic, just experimental filtering.
Re:Quantum Entaglement is not strange at all by Bengie · 2016-09-21 00:06 · Score: 1

It gets better than that. You ball may be a wave or a particle, and you can record the state of the ball now, but in a scrambled form. Then send the paired ball to some someone else who may be millions of light years away. And depending on if they observe it or not, will decide if your ball is a wave or a particle. From your point of view, someone possibly measuring the twin ball millions of years in the future decides if your current ball is a particle or wave.

The issue is that you can't know until data about what they read is sent back allowing you to decipher what you measured. That has to be sent via classical means.
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 00:18 · Score: 0

This is the problem with classical analogies used to describe quantum mechanics, as they simplify things to the point of being wrong outside of the simplest, boring examples, and often falsely convey that quantum isn't that different than classical. This is unfortunate, because the actual quantum behaviour cam be accurately taught using algebra (you an gloss over the details requiring calculus). But if people wanted that, Wikipedia would have answered most of their questions.
Anyway, the specialness of a entangled pair doesn't show up easily with a simple, binary measurement on the entangled particles. Instead use two related measurements, like the direction of spin of a particle like electrons, where you have to pick an axis to measure in, then get a binary result of plus or minus direction. The extra piece of info you need to know, is if a particle has a set spin direction and you measure in an axis perpendicular to that, you have 50-50 chance of getting plus or minus.
Now send Alice and Bob particles with spin entangled such that they are in opposite directions. Now if Alice and Bob measure on the vertical axis, there is always one up pointing spin and one down pointing spin. To demonstrate it is not just an up spin and a down spin particle in two boxes, like the oversimplified example, you can have them measure the spin in the horizontal direction instead. If there were just an up and down spin, measuring horizontal spin would get you left and right 50 percent of the time for each particle, so 25 percent of the time Alice and Bob would both have lefts, and 25 percent of the time they would both get right. But for the entangle pair, they still continue to get only one of each, showing that the particles could not be just in a simple unknown state. There is a global correlation between multiple measurements, which can even be chosen which measurement to make after the entangled pair is split up. So there is no way the original particles had fixed states unless some grander scheme predetermined what kind of measurements when creating the entangled pair.
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 00:23 · Score: 0

Alice asks Bob about his balls...
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 00:46 · Score: 0

Hey, keeping spamming that misleading description of an experiment that is more complicated than necessary to demonstrate the basics ( but severs other purposes). After all, if you say the same thing enough times that people stop pointing out why you're wrong, that must mean you've become correct, right?
Re:Quantum Entaglement is not strange at all by JaredOfEuropa · 2016-09-21 01:24 · Score: 1

So where is Charlie in all this? And the cat? There's a cat in that box too, right?

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If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
Re:Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 01:29 · Score: 0

If a thing collapses to an immutable state upon observation, is it reasonable to say that the collapsed state was always like that and no change happened upon observation?
Using a car analogy: if I cut a car in half and send each half to opposite ends of the world in sealed boxes, then I observe one half, I essentially collapse the state of both halves, but the halves were not in a state of quantum vapour prior to me opening my box. They were always in that state even though I didn't know it.
Now... if the halves were to morph each time I observe them... that would be something cool. Otherwise it's a really fancy way of saying "I don't know yet".
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 01:48 · Score: 0

That's called hidden variables and Bell's Theorem rules that out, at least mathematically.
Re:Quantum Entaglement is not strange at all by bluefoxlucid · 2016-09-21 02:17 · Score: 1

If we can get high reliability, we can encode the detection phase as hamming coding.

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Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 02:20 · Score: 0

"After all, if you say the same thing enough times that people stop pointing out why you're wrong, that must mean you've become correct, right?"
QM is that "repeat it till people stop pointing out why you're wrong" thing.
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 03:11 · Score: 0

A/C, try this :
Remove the coincidence detector. Instead measure the times light arrives at x2 and at the slits.
Now you have a dataset. Post processing that data in a computer, filter the photons for only times you detected the X2 photon. Voila, there are your fringes.
Did the program change the X1 photon? Or did you simply filter out the correct photons from noisy data!
Still not convinced?
OK, split X2 into X2a and X2b, put a horizontal polarizer in front of X2a detector and a vertical one in front of X2b detector. Record all the photons as before.
It would be impossible for X2 to impart a 45 degree polarization because there isn't a 45 degree polarizer there.
Now filter the photons measured at the slit for ones that coincide with X2a and X2b BOTH detection a photon. Voila fringes from X1.
Still not convinced?
Move X2b further away, now the X2 photon hits the vertical polarizer first. You'll need to adjust the timing you measure to compensate for the delay to X2b.
Now, in post processing the results, filter for X2a and X2b... voila... but if it set the polarization it would be vertical...
Re:Quantum Entaglement is not strange at all by GuB-42 · 2016-09-21 04:46 · Score: 2

I know there's a black and a white ball in a box. I pick one of them without looking at it and transport it 10km away, then I check what colour it is. Now I also know the colour of the other ball, but is it fair to say that checking the colour "affected" the ball I left in the box over the distance of 10km? Obviously it's absurd. Why would quantum entaglement be any more mysterious than this?
What you describe here it the hidden variable theory, and it has been proven wrong using Bell's theorem.
Quantum entanglement really is mysterious. Mysterious enough to drive Einstein nuts. And while the maths work, there is currently no satisfactory interpretation.
Re:Quantum Entaglement is not strange at all by kackle · 2016-09-21 05:15 · Score: 1

At least, that's my understanding. I could be wrong, and probably am.
Well, you're right while no one is reading your post. Otherwise, it's wrong. Sorry.
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 07:07 · Score: 0

'Magic' is a satisfactory interpretation.
Re:Quantum Entaglement is not strange at all by wonkey_monkey · 2016-09-21 07:37 · Score: 1

Oh shit. I thought you were feeding the cat.

--
systemd is Roko's Basilisk.
Re:Quantum Entaglement is not strange at all by wonkey_monkey · 2016-09-21 07:38 · Score: 2

Bell's theorem rules out local hidden variables. There might still be non-local hidden variables, but that's just as weird, if not weirder.

--
systemd is Roko's Basilisk.
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-21 07:59 · Score: 0

and gets fired.
Re:Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-22 02:22 · Score: 0

what if you could do the tests in a predetermined order.. OR if you could continuously monitor particle states until you get a match... if there were a way to know what particles would be tested and precisely in which order, wouldn't that work?
Re: Quantum Entaglement is not strange at all by Anonymous Coward · 2016-09-22 07:57 · Score: 0

You can't continuously monitor it as a single measurement of the state of interest forces it into a particular state and breaks the entanglement. And you can't beat it with careful timing, as entanglement can't change the probability distributions of a single end, only of the correlation between both ends. So if without entanglement you had a 50-50 chance of a one vs zero, with entanglement you will still get one half the time and zero the other half. It is only after talking to the person doing measurements on the other end that you will notice there is a correlation, e.g. they always got the opposite of what you got.
Re:Quantum Entaglement is not strange at all by Bengie · 2016-09-23 08:14 · Score: 1

Except you can delay when you cut the car into the future and still get the same result. They can send entangled photons in two different directions, and use different types of measurements to cause statistical influences on the other photon, no matter the distance, and even if it happens in the future. Example is if you measure for vertical polarization, you will get a different distribution than if you measure for horizontal, simplified.

Re: I Think this article might be a bit misleading by Anonymous Coward · 2016-09-20 22:18 · Score: 5, Funny

Exactly. We just need to make sure no flies get into the pods before the doors shut.

Re:I Think this article might be a bit misleading. by Rei · 2016-09-20 22:18 · Score: 5, Interesting

Given that none of the articles, as far as I saw, said anything about faster than light communication, and one explicitly disavowed the concept, I think you're projecting your own mistaken conceptions here.

And your friend is correct - quantum teleportation has nothing to do with faster than light communication, as you can neither determine to what form the waveform has collapsed, nor whether one side has already collapsed it. It's effectively** equivalent to having two identical letters containing a random message sealed in an envelope, taking them to different locations, and opening them at the same time. Both sides will get the same random message at the same time, but it provides no means for conveying information faster than light. It is however useful for keysharing.

** In the real world, what is written inside the "envelopes" isn't determined until it's actually observed. But it works out to the same net effect.

--
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Re:I Think this article might be a bit misleading. by Opportunist · 2016-09-20 22:22 · Score: 5, Funny

Elon, at least log in if you refuse to take your pills.

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Confused by TFlan91 · 2016-09-20 22:25 · Score: 2

Can someone spell this out for us lamens?

How does something teleport across a wire? By that logic, our current communication systems are "teleporting" information.

I thought Quantum Entanglement is instantaneous and void of any connecting wires, which fits my definition of "teleportation" a little better, but I still don't think of it as teleporting.

Re:Confused by Anonymous Coward · 2016-09-20 22:32 · Score: 0

"lamens"? Speaking of spelling things out, what the hell are "lamens"? Are they like lamers?
Re:Confused by Mal-2 · 2016-09-20 22:46 · Score: 4, Informative

Quantum teleportation is instantaneous, but first the entangled particles must achieve some distance between them, and this is subject to the usual speed-of-light constraints. In this case the photons achieved that separation over a length of fiber, rather than being sent through free space. Fiber is likely to scale considerably better than line-of-sight transmission.
Entanglement won't survive optical repeaters, so I'm not sure just how well this actually will scale in the real world. Still, 6.2km is a useful distance for some limited applications.

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Re:Confused by Anonymous Coward · 2016-09-20 22:46 · Score: 2, Funny

It's entanglement of "laymen" and "lamers".
Re:Confused by sabbede · 2016-09-20 23:25 · Score: 1

I was wondering about that myself. The cool part about entanglement is that it occurs without mediation (like a cable), so I was trying to figure out what the big deal was. I guess I forgot that the entangled particles have to be moved from one place to another first and keeping photons in your pocket is tricky. Easy to get them in, hard to get them to stay.
Re:Confused by locofungus · 2016-09-20 23:38 · Score: 1

Quantum teleportation requires the use of a classical channel. The entangled particles can be exchanged in advance (provided they can be stored without breaking the entanglement which is difficult in practice but trivial in theory)
The classical data can only be transferred at the time the teleportation is done - hence that limits the speed of the teleportation to the speed of light.

--
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
Re:Confused by Anonymous Coward · 2016-09-20 23:45 · Score: 0

Quantum teleportation is instantaneous
Definitely *not*. Quantum entanglement is instantaneous, but that's only one part of the puzzle.
To do quantum teleportation you need to transfer the quantum state, encoded in a classical signal, e.g. one or more photons moving at the speed of light.
Re:Confused by Anonymous Coward · 2016-09-20 23:59 · Score: 0

It's entanglement of "laymen" and "lamers".
In utter defiance of idiot-proof automated tools, it's more like an entanglement of "laymen" and "moron".
I'd pay good money for someone to write a plug-in for a spell checker that slaps the shit out of the end user when they ignore it. The comedic value would be worth every penny.
Re:Confused by Anonymous Coward · 2016-09-21 00:43 · Score: 0

In case "lamens" is the French equivalent of "laymen", so you want it in "layman's terms", let me do that for you with a car analogy:
Imagine we have two identical cars, and we replace their carburators with an injection system and then we drive them 7km apart. Quantum teleportation is exactly unlike that.
Or, in other terms, the 7km cable used can wrap around the library of congress at least 15 times.
Re:Confused by Anonymous Coward · 2016-09-21 02:43 · Score: 0

it's more like an entanglement of "laymen" and "moron".
Wouldn't that be mormen?
Re:Confused by Dr.+Evil · 2016-09-21 02:56 · Score: 1

"so I'm not sure just how well this actually will scale in the real world. Still, 6.2km is a useful distance for some limited applications."

FTA, there's another innovation not in the Slashdot headline or summary, except to say " the teams had slightly different set-ups and results."
One of those results seems to be that the team from China's method allows for quantum repeaters which can relay entangled particles:

"...it would allow for the creation of quantum repeaters, to propel the signal further along the network..."
"Now say Bob repeats the process with Daisy, who is 100 kilometres to his right (with another Charlie between them). At this stage, Bob has two particles, one entangled with Alice’s and the other with Daisy’s. If Bob now does a Bell State measurement on his two particles, he effectively entangles Alice’s particle with Daisy’s — stretching teleportation a full 200 kilometres."
“You can scale the whole thing up and can go, in theory, to arbitrarily long distances,” says Tittel.
Re:Confused by Anonymous Coward · 2016-09-21 03:19 · Score: 0

it's more like an entanglement of "laymen" and "moron".
Wouldn't that be mormen?
No, the cross between a layman and and a moron would be a "Mormon".

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-20 22:26 · Score: 1, Insightful

There's no need to be a nerd about it. Some people mistakenly think this news is about fast internet speeds.
some people see "teleported their information" and skim the rest of the article.

Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-20 22:27 · Score: 0

You can see the 'coincidence circuit' again, it's in figure listed in the nature article at the top right corner of Figure 2.

http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2016.180.html

For those who don't know how this works, Photon A is "Entangled" with Photon B. Photon B is sent far far far away.... these photons are claimed to be "entangled in an undefined state". The claim for "spooky action at a distance", is that when Photon A's spin (or similar property) is measured then Photon B's spin is set by the act of measuring 'A's. And when measured it is now the complementary of Photon 'A's.

*However*, all of these experiments include a filtering stage. The photons are split into two and one set is compared. If the photons are correctly 'entangled' then the experimental result is kept, if they are not, then the experiment is discarded as a failed entanglement.

So only experiments where the photons are the same are kept, and if those photons are the same, then they are the same when measured at a distance. The link between the two photons is the experimenter filtering the experiment for 'successful entanglements". The effect is not a "spooky distance effect". It does not happen when the experimenter "measures" the photons property. It happens when the experimenter throws away the experimental results that don't match his desired outcome.

Re:Coincidence circuit again, i.e. filtering by locofungus · 2016-09-20 22:59 · Score: 2

I think you misunderstand.
The experiments that are discarded are where the two end points don't measure the same quantum variable.
For photons, for example, you can measure whether linear polarization is up-down/left-right or diagonal-left-up diagonal-right-down/diagonal-right-up diagonal-left down.
If both ends measure the up-down/left-right state then one will get up-down, one left-right. If both measure the diagonal polarization then again they will get complementary results. But if one measures up-down and the other measures diagonal then we cannot tell anything useful any more than trying to compare two sweets where one person says what shape it is and the other says what flavour it is so those results get discarded.
There is additional statistical analysis - due to the fact that these experiments are done on single photons and sometimes detectors fire when there is no photon and sometimes they don't fire when there is so we cannot expect 100% correlation - but that's nothing to do with discarding some of the results.

--
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
Re:Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-20 23:34 · Score: 0

If Photon A has the same polarization as Photon B at the same time, then it was created at the same point by the same mechanism (in all probability). Photon A and Photon B, must thus have complimentary properties by conservation of momentum when created together. Thus ALL the other properties of A and B are complimentary.
It matters not whether there is a direct relation between the two properties. One is simply used to tag the correct photon pair to look at.
Once you know that Photon A has a property of Photon B and it was emitted at the same time, it follows other properties are also related by the probability of those two things happening at the same time.
Two balls are thrown by my tennis ball launcher, they are rolled together out of the chute and have opposing spins. But my machine throws out lots of balls, sometimes they don't come out of the chute at the same time and so don't touch and don't spin in opposing ways. Bob catches his, and it spins to the right, so by spooky distance effect Alice's spins to the left. Oh but I add one extra stage. Only if the balls pass the detector at the same time do we count the experiment. Since time is unrelated to spin, my spooky distance effect is PROVEN! Because I did not filter for the exact same property.....
Is my tennis machine a quantum machine? No. When the balls pass the detector are they detected? Yes. When your photons are split into two by interacting with a crystal, are they 'detected' by the crystal? Yes, of course, the photon does not know if the atoms its interacting with forms a detector or not. So why do you willfully ignore the big holes in your experiments?
Re:Coincidence circuit again, i.e. filtering by locofungus · 2016-09-20 23:50 · Score: 3, Informative

You got the first paragraph right. But then got sidetracked by tennis balls.
There are *two* complementary quantum states that you can measure. Measuring one destroys all knowledge of the other.
There is no classical system that behaves like this, therefore any analogy that doesn't invoke some magic artificial property of a classical object won't represent what happens in QM.
In your example you need tennis balls that randomly change colour when you measure their spin and can magically reverse spin when you look what colour they are.

--
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
Re: Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 00:33 · Score: 0

The time filtering is because down detectors will get occasional background photons and some entanglement sources are not perfect at emitting only entangled pairs, so occasionally a single photon comes out instead of a pair. The experiment can and is done without time filtering, but the time filtering lets you use cheaper equipment and a setup simple enough to work for an undergrad lab course. The error rates in setups without the filter are low enough that you're not just cherry picking your results, which is seem by simple statistics. Fixating on the filter as if it were cherry picking would normally belay a large hole in your understanding of what the experiments actually do to anyone familiar with decades of work, not instead as you suggest, show some big hole in the experiments. But if you're the same person who has been making similar posts for years on Slashdot despite careful, cited rebuttal s, it is not a simple lack of understanding, but a willful misinterpretation and refusal to learn about the subject and/or trollish deception.
Spamming an idea on every quantum mechanics story until knowledgeable people get too tired of replying in detail or with citations, or until an unknowledgeable person makes an honest mistake, so you can then claim no one counter you criticism, is a flat out lie. The question then becomes are you lying to yourself, or just a troll lying to others.
Re: Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 00:35 · Score: 0

Sigh, this is what happens when schools only teach Newtonian physics. I think the problem is you don't understand the math behind these experiments. You have to understand that particles like photons don't work like balls - their states are random and not determined at their creation like with macro objects. The state of a particle is given by a probability function and not an absolute value like with macro objects. So while you can very accurately predict where your balls with land using traditional physics, your photons will land along a probability curve and you can never be sure where the next will hit. There have been experiments that have proven this without a doubt - Einstein called it spooky action at a distance because at the time they only had the mathematical models and he didn't believe they were correct, but a century of science has all backed up the math. I specifically suggest you check out the double slit experiment and the quantum eraser experiment.
Re:Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 00:41 · Score: 0

"There is no classical system that behaves like this, therefore any analogy that doesn't invoke some magic artificial property of a classical object won't represent what happens in QM."
Or polarization is a property of spin and spin a property of polarization. i.e. there is not two but one property. No magic collapse occurs when you measure one of them.
The tennis balls does not reverse spin, if they came out of the machine at the same time, they picked up some of the same colored paint and have complimentary spins from touching (at the same time). i.e. both properties derive from one thing. It matters not that I can plot Bob's measured spin, and the paint coor on the ball and they have zero correlation between spin angle and ball color.
Re:Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 00:48 · Score: 0

"complementary", not "complimentary".
Re:Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 01:25 · Score: 0

ok, so the tennis balls have opposite spin due to how they were launched; they also have the same color due to the paint rubbing off during launch.
The missing part of the analogy is that, "magically", if either Bob or Alice look at one of the properties of the ball they got, they cannot also look at the other property. If say, Alice checks what *color* her ball is, she loses the chance to check the ball's spin. Same with Bob.
So, they discard experiments where one of them looked at color and the other looked at spin, and keep the ones where they both looked at the same thing: color-color, or spin-spin.
The balls don't magically change color or spin when examined. The only magic is that with a physical ball I *could* tell both color and spin, but with a quantum one I can only ever check one, then lose the chance to check the other.
Now: how again is this useful for encryption ?
Re:Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 01:48 · Score: 0

No magic about it. You are discussion Quantum Encryption, I am discussing Quantum entanglement.
I think we've been talking at cross purposes. I'm explaining how having two properties that derive from a single property or event can have no correlation, i.e. be provably independent and yet collapse to be one when measuring seemingly separate chosen instances.
In my example, they were the balls color and its spin. Unrelated, probably uncorrelated and yet, because I explained how the tennis machine worked, you can see how despite this, the two balls will have the same properties if I select the subset of those balls based on time of firing.
That was a means to showing you (I thought) how the QM proof has a very very basic logic flaw in it.
But then you talk about encryption, oh well...
Re:Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 04:22 · Score: 0

Random AC on Slashdot knows more about "basic logic" and how it applies to modern physics than the century's worth of physicists and mathematical physicists that came before you.
I look forward to your latest Journal article that completely destroys QM and restores classical mechanics to its former glory. I'll keep an eye on Nature Physics and Reviews of Modern Physics for your brilliant analysis. Might I recommend the title: Staring at Newton's Balls: Tennis and Reality
Quantum physics is hard. All that math and stuff. Time to put a stop to it, and bring back classical physics. They've got to be the same, right? Just without the stuff I don't understand and thus believe must be physicists appealing to magic.
Re:Coincidence circuit again, i.e. filtering by CustomSolvers2 · 2016-09-21 05:11 · Score: 1

Not sure about what is the current glory of classical mechanics, but I am quite sure about its actual applicability: everywhere with eventual corrections (although virtually any theory has to be corrected for real-life applications; reality is still too complex for us). Logically, I cannot say anything about the glory of modern physics, much less to someone relying on so solid arguments like "some smart people think that it is right".

FYI and just in case you don't have a mirror at hand, you are also an AC (not sure if a random one though).

--
Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.
Re:Coincidence circuit again, i.e. filtering by CustomSolvers2 · 2016-09-21 05:47 · Score: 1

Also perhaps I am a bit weird, but shouldn't a theory meant to help understand a given phenomenon to be easy to understand itself? I get that the more complex is the phenomenon, the more difficult to understand even the easiest theory; but isn't this kind of bragging about the complexity of a theory a bit pointless? Shouldn't it be the contrary? Feeling a bit ashamed about not having been able to come up with a clearer approach?

A mistrustful person might even say that too/unnecessarily complex approaches are the typical outputs of either ignorance or dishonesty. On the other hand, you have religions, where the difficulty to understand is quite common ("only god knows") and a blind trust is usually required ("trust in god").

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.
Re: Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 08:06 · Score: 0

Check out Feynman's description of the double-slit experiment on those old black and white movies floating around at YouTube.
Amazing. Even he shrugs his shoulders, but there is the data...
https://www.youtube.com/watch?v=2mIk3wBJDgE
Re:Coincidence circuit again, i.e. filtering by Anonymous Coward · 2016-09-21 17:56 · Score: 0

(Not the same AC(s) as above)

but shouldn't a theory meant to help understand a given phenomenon to be easy to understand itself?
No, there is no reason or expectation that nature is defined by simple rules, especially simple/easy to any given person. And what is simple to one person may not be simple to another, e.g. things that can be expressed very concisely and practically with math that have problems when trying to shoehorn into a description with imprecise words.

Feeling a bit ashamed about not having been able to come up with a clearer approach?
Sometimes it is a failure to be a good teacher, whether not understanding the subject or student as well as hoped, but sometimes it is just about irreducible complexity.

A mistrustful person might even say that too/unnecessarily complex approaches are the typical outputs of either ignorance or dishonesty.
In this context, consider the vast volume of freely available information on quantum mechanics, especially the unabridged versions requiring just some basic calculus, or the slightly abridged versions only requiring algebra, both of which lack the severely imperfect analogies of mathless popsci. Mistrusting a subject that the basics of which can be picked up in a couple weeks of free time for most people on Slashdot is more a personal problem than a problem with the subject material. I say this not theoretically, but from having taught "modern physics for engineers" courses before where less than half a term is enough to cover quantum mechanics basics to non-physics students.
It is understandable if a person doesn't want to put that time into a particular subject, but that is a long, long way from suggesting a need for blind trust or that the material is purposely obtuse.
However, what is less understandable to downright sad, is the amount of time people put into discussing a subject they proclaim to be personally important and/or of great personal interest, yet show they haven't bothered to try learning about the basics using even a modest fraction of that time. With QM in particular, even skipping the math, one could learn about the variety of experiments to get some idea of the breadth and scope involved, instead of extrapolating from a superficial understanding of just one or two experiments. While experts can easily be wrong, thinking one can prove them wrong in a field of science with such a shallow understanding of even just what observations have been made says little of the complexity of a subject (I've seen crack pots challenge Maxwell's equations and Newton's laws in ways that would could be proven wrong by high school level experiments that could be done with $10-20 of common hardware).
Re:Coincidence circuit again, i.e. filtering by CustomSolvers2 · 2016-09-21 21:30 · Score: 1

First of all, thanks for self-identifying (sometimes, it is quite difficult to keep track of the AC you are talking to).

Sorry about that but I am afraid that you misunderstood my message; I was kind of sarcastically pointing out some of the problems I see here. Ironically and right before writing this message, I did write another one showing my honest intention of reducing the sarcasm content in my online contributions (what can I say? I couldn't refrain myself :)).

I am sure that other readers will appreciate your nice clarifications, but certainly not me (I mean... I appreciate you being so nice; I always appreciate people trying to help others, that's why I am feeling a bit bad about the misunderstood sarcasm). I do have a quite solid mathematics and physics knowledge (mainly about on the practical engineering versions); difficulty hasn't ever scared me (I am an engineering/science/going-always-beyond kind of person for whom the only goal is actually knowing more; not the kind of person who is afraid of difficulties); and, although I am always ready to learn more (a proud constant learner), I certainly don't want to know more about QM.

Again, sorry for the misunderstanding and thanks for having tried to be helpful.

--
Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Why Alice Bob and Charlie? by OzPeter · 2016-09-20 22:28 · Score: 1

I always thought that it would be apropros to use Bob, Carol, Ted and Alice as example names for sharing.

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Re:Why Alice Bob and Charlie? by Bromrrrrr · 2016-09-20 23:10 · Score: 3, Funny

I always thought that it would be apropros to use Bob, Carol, Ted and Alice as example names for sharing.
Ted and Alice broke up, though he doesn't know it yet.

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What a rotten party, have we run out of beer or something?
Re:Why Alice Bob and Charlie? by wonkey_monkey · 2016-09-20 23:12 · Score: 1

What about Rita, Sue and Bob too?

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systemd is Roko's Basilisk.
Re:Why Alice Bob and Charlie? by Anonymous Coward · 2016-09-21 01:46 · Score: 0

I've always been partial to Inky, Pinky, Blinky, and Clyde.
Re:Why Alice Bob and Charlie? by Fire_Wraith · 2016-09-21 01:59 · Score: 1

That's not nearly as effective at getting Computer Scientists to listen to whatever boring story you have to tell, though:
http://xkcd.com/1323/

Fiber network? What fiber network? by Anonymous Coward · 2016-09-20 22:39 · Score: 1

"Calgary's fiber optic network that's not regularly in use."
Yeah no shit it's not in use. ISPs build the network and leave it there for years just to keep getting as much money out of their outdated tech... and when they finally give us fiber, they start with very low speeds (under 100Mbps), at ridiculous pricing, to gouge us even more.

Re:I Think this article might be a bit misleading. by Viol8 · 2016-09-20 22:49 · Score: 2

If that random message is used as the key then it is transporting information since information is simply data that has a meaning or use.

Re:I Think this article might be a bit misleading. by Maritz · 2016-09-20 22:55 · Score: 1

Yeah. You can send random information faster than the speed of light. Not useful.

--
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.

Re:I Think this article might be a bit misleading. by Rei · 2016-09-20 22:57 · Score: 2

information since information is simply data that has a meaning or use.

Data that to an observer is 100% random is not "transmitted information" in a physics context. Or in an information theory context either

--
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Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-20 23:03 · Score: 1

Yeah. You can send random information faster than the speed of light.

No. You can't.

--
systemd is Roko's Basilisk.

Re: I Think this article might be a bit misleading by Anonymous Coward · 2016-09-20 23:07 · Score: 0

Not all of you. They'll just get your ass to Mars. Bzzzzt.

Re:I Think this article might be a bit misleading. by 110010001000 · 2016-09-20 23:08 · Score: 1

So basically you are saying that Star Trek style transporting is possible? Exciting news!

Re: I Think this article might be a bit misleading by Anonymous Coward · 2016-09-20 23:23 · Score: 5, Funny

Umm, this is Slashdot!

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There's no need to be a nerd about it.

Re:I Think this article might be a bit misleading. by locofungus · 2016-09-20 23:25 · Score: 5, Informative

It's effectively** equivalent to having two identical letters containing a random message

No. you're describing entanglement.

Teleportation is subtly different.

Teleportation consists of transferring the quantum state of one particle to another particle via the use of entangled particles (and a classical channel)

The beauty of this is that the entangled state can be set up in advance. You then give me a particle that you might or might not know something about its quantum state (but importantly, I do not know what you know about it so cannot measure that quantum state in advance). I can transfer the state of that particle to another particle that Bob has via some entangled particles we exchanged earlier *plus* some standard classical information that goes over classical channels (it's this classical information that limits the teleportation to the speed of light)

The particle that Bob ends up with is in an identical state the the one you gave me (and which I still have).

N.B. This is quantum teleportation, not quantum cloning which is not possible. The act of getting the quantum state to Bob affects my particle in a way that means I cannot also extract any information from it about the original state of your particle.

--
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.

I hate to break it to you ... by Qbertino · 2016-09-20 23:32 · Score: 1

... but if you need a cable, it's not teleportation.

Just sayin'.

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We suffer more in our imagination than in reality. - Seneca

Re:I hate to break it to you ... by Anonymous Coward · 2016-09-21 00:50 · Score: 0

You miss the point. The teleportation happens at the moment of measurement of particle in either Alice or Charlie's end. The information is transfered via normal means, but the states are revealed via entanglement, a.k.a. teleportation of information when measured.

This is not teleportation by mrlinux11 · 2016-09-20 23:49 · Score: 1

Teleportation or teletransportation is the theoretical transfer of matter or energy from one point to another without traversing the physical space between them. It is a common subject in science fiction literature, film, video games, and television.

Re:This is not teleportation by wonkey_monkey · 2016-09-21 21:56 · Score: 1

Words can mean different things in different contexts.

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systemd is Roko's Basilisk.

Re: God by slashrio · 2016-09-21 00:01 · Score: 1

I'm very sorry, but I HAVE to steal that signature! :)

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"Trump!!", the new Godwin.

Homeopathy by TJHook3r · 2016-09-21 00:10 · Score: 1

People who scoff at 'memory of water' are going to shit their pants when they read about this!

'Teleportation' ? by Anonymous Coward · 2016-09-21 00:13 · Score: 0

So 'sending quantum information across optical fiber networks' is 'teleportation' now ?

Note to /. editors : stop making overly sensationalist headlines. Please.

Re:'Teleportation' ? by tnk1 · 2016-09-21 04:29 · Score: 1

The system uses quantum teleportation as part of the communication system.
The title may be a little sensational, but only because most people think quantum teleportation means physical teleportation. No one who really knows what QT is thinks that it is a revolutionary breakthrough in FTL communications.
Quantum teleportation is cool, but not in the revolutionary way that physical teleportation would be.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-21 00:22 · Score: 1

so the key isn't data?

Can Anyone Explain This To Me? by Anonymous Coward · 2016-09-21 00:28 · Score: 0

I've not been able to wrap my head around quantum teleportation, mostly because none of these stories tell what the critical components are?

What is the particle?
What is the "information"? Is it a bit, a string, something else?
What is the key? Is it an encryption key, like 256 bit AES or is it something else?
What is physically being measured and how?

The "simplified" analogy talks of Bob creating an entangled pair; how is the entanglement created?

If the act of measuring changes the state, how can the state be measured? Are they saying that they can see the state, but that the state changes after they have seen it, or does it change when seen, so you never see the previous state?

It would be a lot easier for me to understand if someone explained the mechanics, e.g an LED at point A produces a light and a receiver at B sees the light...

Re:Can Anyone Explain This To Me? by ledow · 2016-09-21 00:44 · Score: 2

Particle could be anything, probably sub-atomic to actually work, so it barely matters what atom is actually SENT down the wire. Most likely a photon, though, in these cases though you can do it with electrons and similar.
Information is probably not much per attempt. Maybe as low as a bit each time. But that's enough to form a bitstream. Slow, but a bitstream. That means you can send a conventional PKE key or DH exchange using it because they are small but need to be transmitted securely.
You're measuring a property of the photon. Most likely a particular Bell State (google it) that it falls into.
Measuring that is HARD.
Entangling it is harder.
Measuring the state actually destroys the "connection", as such - like ripping open the envelope means you can't reseal it without someone noticing something has changed.
Thus, you can't measure the state AND then pass it on as the original. Which means you can't interfere with a message without people knowing, and then they throw that message / key away and make a new one.
And quantum teleportation is when something is in an entangled state. You send it anywhere in the universe. You measure it. And THAT MEASUREMENT determines what the particle was all along, everywhere, in all the universe, immediately, without care of the speed of light (Quantum stuff is WEIRD).
Think of it as not "putting a message into a particle" but as "revealing what universe you WERE already in". When you measure, you know EXACTLY what universe you are in NOW, for that time of measuring. But it could be any universe and you could end up measuring all kinds of values. But in YOUR universe, for THAT measurement, your special code is whatever you measured. There's no way to determine that before you measure.
But as soon as you know that, you know what everyone else sent too because of the universe you happen to be in.
It's like being at a murder mystery party and not knowing that the murderer was YOU until the very end. when you measure them all. Even though you've already killed the guy, you didn't know until that point.
Quantum stuff is weird. It's never going to be easy to understand.
Re:Can Anyone Explain This To Me? by locofungus · 2016-09-21 00:49 · Score: 1

0 - 1 \ | / \ | / \|/ ------- + /|\ / | \ / | \

--
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
Re:Can Anyone Explain This To Me? by locofungus · 2016-09-21 01:16 · Score: 2

Oh well. I tried to write a comment with a diagram but hit submit instead of preview :-(
Consider four directions on a plane. x axis (we'll call that |+>), y axis (we'll call that |->) y=-x (we'll call that |0>) and y=x (we'll call that |1>)
Modulo some constant factors, I hope it's obvious that you can build up some of those vectors from others:
|1> = |+> + |->
|-> = |0> + |1>
etc.
These are the directions of a plane polarized photon.
We setup some photons that are polarized in the |1> direction and then pass them through a polarization filter.
If the filter points along the |1> direction then all of them pass. If the filter passes along the |0> direction then none of them pass.
Now we put the filter along the |-> direction. What happens.
|1> = s|+> + s|-> (s is 1/sqrt(2) - which can be deduced from standard trig - the lines must be the same length)
When we measure along the |-> direction the s|-> part will pass the filter but the s|+> part wont.
But an individual photon can't get dimmer therefore it must either pass or not. Half the photons do pass and half don't (and it's random whether any one photon gets through the detector)
The ones that do get through are now in state |-> which is also |0>+|1> (again with factors of sqrt 2)
If we now measure along the |1> direction again we now lose half the photons again (due to that |0> component)
Quantum teleportation involves taking a photon in state a|0> + b|1> (for unknown values of a and b) and taking very careful measurements that don't destroy a and b but instead transfer them to another photon without us actually knowing what they are.

--
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-21 00:28 · Score: 0

Can't you?

I send you 1000 particles on a silver platter, through slower-than-light methods. They're entangled with particles I keep myself.

Once you are in the possession of them, I modify the state of my own particles, which will modify the state of the ones you have as well. You will detect those modifications instantly, when I make them. Or "faster-than-light".

What we cannot do is communicate _information_, since we didn't know the states beforehand, which the OP alluded to in saying that we can "send random information".

Is my understanding wrong?

Re:I Think this article might be a bit misleading. by stealth_finger · 2016-09-21 00:47 · Score: 1

Given that none of the articles, as far as I saw, said anything about faster than light communication, and one explicitly disavowed the concept, I think you're projecting your own mistaken conceptions here.

And your friend is correct - quantum teleportation has nothing to do with faster than light communication, as you can neither determine to what form the waveform has collapsed, nor whether one side has already collapsed it. It's effectively** equivalent to having two identical letters containing a random message sealed in an envelope, taking them to different locations, and opening them at the same time. Both sides will get the same random message at the same time, but it provides no means for conveying information faster than light. It is however useful for keysharing.

** In the real world, what is written inside the "envelopes" isn't determined until it's actually observed. But it works out to the same net effect.

It seems to me that they could very well use it for ftl communications. If you can change the state of one particle to a state that represents either a 1 or 0 then the other will change to match it so you just read the state of the recipient and then you have a binary stream. The bandwidth might not be especially great and on an earthly scale you'd probably still get a better data rate over traditional methods. Although I am not a expert in such fields, not even an amateur and there are probably a bunch of reasons that won't work but still, if you can control one to read the other I don't see why not.

--
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Re:I Think this article might be a bit misleading. by jbmartin6 · 2016-09-21 00:47 · Score: 1

My education in physics is limited, maybe you could attempt to clarify why the classical channel is required? I thought that once the two ends were entangled they would reflect each others state without any intervening communication.

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Re:I Think this article might be a bit misleading. by jbmartin6 · 2016-09-21 00:48 · Score: 1

AH never mind , NOW I find the explanation posted later.

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This posting is provided 'AS IS' without warranty of any kind, implied or otherwise.

Better to work on quantum DEPORTATION! by Anonymous Coward · 2016-09-21 00:55 · Score: 0

and get rid of all the muzlumz

VOTE TRUMP 2016
MAKE AMERICA GREAT AGAIN!

Case Closed by Anonymous Coward · 2016-09-21 00:57 · Score: 0

Mystery solved.

Quantum entanglement is a shitty penis bird.

Re: I Think this article might be a bit misleading by bev_tech_rob · 2016-09-21 01:00 · Score: 2

Exactly. We just need to make sure no flies get into the pods before the doors shut.

And since we are beaming ourselves over fiber, pray that backhoe fade doesn't hit while transporting....

--
You're messin' with my Zen Thing, man.....

Still Muddy by Anonymous Coward · 2016-09-21 01:07 · Score: 0

Still muddy, but better. Thank you.

communication gateways w/o latency? by strstr · 2016-09-21 01:15 · Score: 1

think about it. two particles, linked. you could scan the particles and send signals through them with interferometry. also the signals would be harder to intercept possibly, because the communication was only between the two particles. you would have to do a global scan to intercept the signal. they actually already have that- complete hologram scanning, and signals intelligence to create holograms anywhere they want- even inside our minds for torture, surveillance, and synthetic telepathic communications.

O_O.. drrobertduncan.com

Re: communication gateways w/o latency? by Anonymous Coward · 2016-09-21 02:03 · Score: 0

You are a lunatic.
Re:communication gateways w/o latency? by wonkey_monkey · 2016-09-21 07:42 · Score: 1

you could scan the particles and send signals through them
Nope. Doesn't work like that.

--
systemd is Roko's Basilisk.

Sigh is not science by Anonymous Coward · 2016-09-21 01:20 · Score: 0

"The state of a particle is given by a probability function and not an absolute value like with macro objects."

No, the OBSERVATION of the state of a particle is given by a probability function and not an absolute value. And this observation effect occurs at macro scale too.

At macro scale I usually try to get people to imagine a flock of starlings with their glasses off. They can observe the flock, but not the individual birds. The flock jumps and swirls and obeys a probability function. It is exactly the same effect at every scale wherever the detector cannot observe the thing, but only a macro scale representation of that. The flock swirls, jumps around, appears in two places at once as if it travelled in time.

A mathematical model of the flock of starlings, is not a proof of their time travelling behavior, their spooky distance jumping nature. It's just a smaller bird, we cannot see except in the flock.

So without a proof, what do you have? A claim that setting a property in one photon, ripples back through time and space and changes that property for every related photon that it interacted with in the past. And a wilful blindness to all the places that photon is interacting with matter that could be turned into a detector.

"your photons will land along a probability curve and you can never be sure where the next will hit. There have been experiments that have proven this without a doubt"

As long as you cling to the wave function you cannot understand the nature of matter and the nature of waves.

Re:Sigh is not science by Anonymous Coward · 2016-09-21 05:37 · Score: 0

Oh FUCK, it's the "flock of starlings" guy! You're the nuttiest nutbar that ever nutted all over a website! And I read Khyber's comments! Compared to you, he's a calm rational adult!
Why don't you at least change the type of bird once in a while?
Re:Sigh is not science by Anonymous Coward · 2016-09-21 12:32 · Score: 0

It is exactly the same effect ...

Not even close. A whole flock of birds doesn't disappear when you observe a single bird at a particular location, but that does happen for wavefunctions. More formally, you're analogy would disagree with both Bell's inequality and simpler experiments.

Re:I Think this article might be a bit misleading. by Salgak1 · 2016-09-21 01:29 · Score: 1

Scott us up, Beamie!

Re:I Think this article might be a bit misleading. by locofungus · 2016-09-21 01:30 · Score: 1

I don't know what else you saw but basically the entanglement leaves the target (teleportation) end in a superposition of four states, only one of which is the one you want the others are complementary states.

The sender makes a measurement at their end to determine which one of the four states is the correct one and then transmits it to the receiver. The receiver can then isolate the correct state from the others that would otherwise cancel out all knowledge of the original state.

--
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.

Re: I Think this article might be a bit misleading by Anonymous Coward · 2016-09-21 01:43 · Score: 0

Yes your understanding is wrong. You took Charlie out of the equation

Re:I Think this article might be a bit misleading. by Maritz · 2016-09-21 01:46 · Score: 1

Amazing rebuttal. Yes, you fucking can.

--
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.

Re: I Think this article might be a bit misleading by Anonymous Coward · 2016-09-21 01:50 · Score: 0

But the classical channel *is* needed to complete the teleportation. You can prepare any state you want, but in order to the other lab you have to measure your system, and send an email with the reading in your equipment.

Part of the appeal of teleportation is that you can send a state that you *don't* know which is. And the determination of the state of a single copy is not possible in QM

Re:I Think this article might be a bit misleading. by nikkipolya · 2016-09-21 02:14 · Score: 1

The method used has deep implications for security and encryption methods, but not faster than light data transfer. Just wanted to clear that up.

The parent explicitly says that faster than light data transfer is not possible. It's really sad we are unable to capitalize on the 'spooky action at a distance' phenomena.

Re:I Think this article might be a bit misleading. by bluefoxlucid · 2016-09-21 02:14 · Score: 1

A key *is* information.

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Re:I Think this article might be a bit misleading. by Baleet · 2016-09-21 02:27 · Score: 1

How is the key not a form of information?

Re:I Think this article might be a bit misleading. by Dunbal · 2016-09-21 02:53 · Score: 1

Uh huh. Tell you what, I just sent you an instantaneous message. I will now send you via snail mail the key to decrypt it.

Exactly how fucking useful is that?

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Seven puppies were harmed during the making of this post.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 02:53 · Score: 1

No, you can't, and adding an expletive does not make you correct.

You cannot send random, or any other kind, of information faster than light. That's just not what entanglement/collapse does.

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 03:01 · Score: 1

Once you are in the possession of them, I modify the state of my own particles, which will modify the state of the ones you have as well. You will detect those modifications instantly, when I make them. Or "faster-than-light".

Nope. You can't "modify" anything - you can only make a measurement. And I can't "detect" anything either - I can't tell whether or not you've made a measurement at a certain time (not least because "at a certain time" takes on an indeterminate meaning over distance).

All either of us can do is make a measurement. When I do, which could be before, after, or at a time with an indeterminate relation to yours (thanks to special relativity and relativity of simultaneity) I will find - upon comparing it to a classical transmission from you, telling me what result you got - that I got the same (or a complimentary) result to you.

But what that result is is effectively random. And even then, it isn't a transmission of information. Without the classical confirmation, all I can do is infer that you got a correlated result - you might have messed up, broken the entanglement, and jiggled the photon to a random, uncorrelated state. Or you might have not bothered to make measurement at all, having been eaten by a velociraptor that escaped from the paleoclonology department.

At this point people start wondering why we can't just assume that the photon had this "state" already encoded in it before (as a "hidden variable"). Well... we just can't. Experiments have proved this. It's just weird.

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by Wulf2k · 2016-09-21 03:04 · Score: 1

That would be incredible fucking useful if you could send a series of encrypted messages to anybody that knew morse code.

This isn't even that.

Faster than the speed of light? by Anonymous Coward · 2016-09-21 03:24 · Score: 0

So was the "data" that was transmitted measurably faster than the speed of light?

Re:Faster than the speed of light? by Anonymous Coward · 2016-09-21 06:52 · Score: 0

No, you cannot transport information faster than the speed of light. There are no tricks or loopholes around this.

Re:I Think this article might be a bit misleading. by hey! · 2016-09-21 03:28 · Score: 1

In a sense you could interpret it that way. But that's quibbling about terminology; it doesn't mean you can send messages that way, which is the important point.

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Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.

FTL WTF? by Anonymous Coward · 2016-09-21 03:29 · Score: 0

Consider this...

Bob gives Charlie a couple of million entangled particles, leaves Earth and travels to Alpha Centauri.

Both Alice and Charlie sit on the same planet.

At 2100-01-01T00:00:00Z Alice gives her message in form of particles to Charlie, who does the "Bell state measurement" dance and combines Alice’s particle #1 with Bob's particle #1, etc.

Bob measures his particles at 2100-01-02T00:00:00Z.
Was the message transferred FTL?

Re:FTL WTF? by GuB-42 · 2016-09-21 05:39 · Score: 1

Was the message transferred FTL?
Nope, because the universe doesn't like it.
In this particular case the problem is that we don't know beforehand which particle is entangled with witch one. Some particles may not be entangled at all. The result is that by measuring his particles, Bob will only get random data.
The only way for him to find the "good" particles is by comparing his measurement with Alice's, but first, Alice has to transmit her results, and this can only be done the "slow" way.

Re:I Think this article might be a bit misleading. by shnull · 2016-09-21 03:33 · Score: 0

Someone explained this news to me recently, they said the scientists didn't send ~information~ over quantum entanglement, they sent the data across normal networking means and sent and a key to unlock the data via quantum entanglement. The method used has deep implications for security and encryption methods, but not faster than light data transfer. Just wanted to clear that up.

thats a dam shame and also more like cheating and hacking it ... i was already having visions of the beginning or the beginning of the end for all religion and the soul ... matter transmission ... if you can decode the totral string of numbers that make up one homo sapient and you send it over 7 km does it arrive with a soul or not in most cases the difference would be hard to see since bootsy collins would be hugging most of the available soul in the observable universe and the standard pseudo sapient is actually little more than a well-conditioned automaton but it might get rid of pesky fanatics once and for all gully foyle ... the stars my destination don't beat yourself up over it scotty, they were just emulating ?

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beware he who denies you access to information for in his mind, he already deems himself to be your master (SMAC-ish)

Re:I Think this article might be a bit misleading. by shnull · 2016-09-21 03:36 · Score: 0

wopp, sorry for the doublepostreplytomyself but i was faster than me as usual i was just thinking in order to jaunt ... its gonna be a drag getting that cable to proxima centauri first

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beware he who denies you access to information for in his mind, he already deems himself to be your master (SMAC-ish)

Re:I Think this article might be a bit misleading. by michelcolman · 2016-09-21 03:38 · Score: 1

So that's why Tesla and Solarcity stocks are down today!

Re:I Think this article might be a bit misleading. by tnk1 · 2016-09-21 03:39 · Score: 1

I think in some sense, the particles are never actually separated, when though their x,y,z coordinates change in 3D space. It may make more sense to think of them as still actually connected in some domain, but that their projection in space has changed so that they seem to now be separated when only looking at spatial coordinates.

Re:I Think this article might be a bit misleading. by JesseMcDonald · 2016-09-21 04:05 · Score: 1

What is being "communicated" FTL, without a non-FTL classical channel, is a random superposition of all the possible quantum states. That is not "random information", it's "no information". Without the classical channel you don't even know whether the holder of the other entangled particle is measuring the same quantum states, so no information is exchanged, not even information about the measured states of the entangled particles.

But sure, as a trivial special case, it is possible to exchange zero information at FTL speeds...

--
"The state is that great fiction by which everyone tries to live at the expense of everyone else." - Bastiat

Re:I Think this article might be a bit misleading. by OakDragon · 2016-09-21 04:13 · Score: 1

No. This article clearly means we'll be transporting ourselves to Mars before the week is out.

It doesn't happen that fast. Based on news like this we've heard in the past, though, transporting to Mars is just 10 years away.

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Dark Reflection

Re:I Think this article might be a bit misleading. by sexconker · 2016-09-21 04:23 · Score: 1

NOTHING is being transmitted FTL.
You entangle particles, separate them at speeds = c, then you measure them.
The information transfer is in the separation of the particles at speeds = c.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-21 04:35 · Score: 0

You never did explain how quantum teleportation is different than the letters.

Re: I Think this article might be a bit misleading by blind+biker · 2016-09-21 05:09 · Score: 1

It also helps if the teleportation doesn't turn our insides out.

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"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.

Re: I Think this article might be a bit misleading by Anonymous Coward · 2016-09-21 05:20 · Score: 0

Make sure the Schroedinger cat got there first.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-21 05:21 · Score: 0

Or at most, a decade.

Re:I Think this article might be a bit misleading. by Gavagai80 · 2016-09-21 05:24 · Score: 1

A key is only information if it's a specific key. If you ask me for my key, you're requesting information. If you ask me for a key, then random data suffices.

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Re: I Think this article might be a bit misleadin by Anonymous Coward · 2016-09-21 05:46 · Score: 0

They found out later it was the information from someone torrenting...

Re:I Think this article might be a bit misleading. by TechyImmigrant · 2016-09-21 05:46 · Score: 2

Someone explained this news to me recently, they said the scientists didn't send ~information~ over quantum entanglement, they sent the data across normal networking means and sent and a key to unlock the data via quantum entanglement. The method used has deep implications for security and encryption methods, but not faster than light data transfer. Just wanted to clear that up.

Quantum Key Distribution: More expensive and less practical that putting the key on a USB stick and driving it to the other end.

--
I should use this sig to advertise my book ISBN-13 : 978-1501515132.

Re:I Think this article might be a bit misleading. by TechyImmigrant · 2016-09-21 06:05 · Score: 1

information since information is simply data that has a meaning or use.

Data that to an observer is 100% random is not "transmitted information" in a physics context. Or in an information theory context either

Bullshit. It is transmitted along the fiber optic cable, at a fraction of the speed of light in a vacuum, to yield the same random value at both ends. By being unpredictable, it meets the definition of information.

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I should use this sig to advertise my book ISBN-13 : 978-1501515132.

Re:I Think this article might be a bit misleading. by TechyImmigrant · 2016-09-21 06:07 · Score: 1

In a sense you could interpret it that way. But that's quibbling about terminology; it doesn't mean you can send messages that way, which is the important point.

Well you can, you just can't choose which message is sent, from the space of all possible messages sendable.

--
I should use this sig to advertise my book ISBN-13 : 978-1501515132.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-21 06:16 · Score: 0

I've never fully understood why a signal can't be transmitted instantly across large distances using quantum entanglement. So measuring one particle instantly changes the other one but WHY can't that be used to send a bit (or something). Have a clock that toggles on and off so you know when to read the other particle. Okay, so if you are thinking that measuring the particle alters it and that's the reason why we can't do it then HOW can it even be used for encryption? How is it useful at all?

This layman needs further explanation by SDLeary · 2016-09-21 06:21 · Score: 2

OK, slight background. Basic applied physics knowledge from 20+ years ago.

How does this qualify as teleportation if you have an optical particle, and a optical transport medium? Isn't this the photon hitting the surface of the fiberoptic transport medium, changing state to an optical waveform, traveling along the transport to the endpoint, exiting and changing state again, and then being detected as a photon?

Also somewhat confusing as photon's have no mass.

If this had been a neutron, or some other actual subatomic particle with mass, then I could certainly conceptualize it as teleportation. Couldn't this simply be the researchers finding a "sweet spot" in "transmission frequency" for said optical fiber to allow transmission nearer theoretical maximum (i.e. the speed of light). Have they tried the same experiment on a different optical fiber from a different vendor and achieved the same results?

SDLeary

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-21 06:22 · Score: 0

But what that result is is effectively random. And even then, it isn't a transmission of information.

That's what the OP wrote, and I wrote, yes.

Ya know... by fahrbot-bot · 2016-09-21 06:26 · Score: 1

Alice, Bob, and Charlie show up a LOT in these types of discussions. Mucking around with quantum this and quantum that. Sending encrypted messages. Very suspicious. Why aren't they on some sort of watch list?

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It must have been something you assimilated. . . .

Re:Ya know... by Anonymous Coward · 2016-09-21 22:35 · Score: 0

Why aren't they on some sort of watch list?
What makes you think they're not?

Explaining FTL non-information travel by cellocgw · 2016-09-21 06:43 · Score: 2

My favorite way to explain the difference between something "happening" FTL and useful information not being able to travel FTL is this:

Imagine you've got a powerful laser aimed at a wall a few light-years away. You then sweep the laser beam along the wall's length. The illuminated area changes at several times the speed of light. But this is not information transfer, because each photon travelled a few years in a straigh(ish) line and hit the wall based on the angle of the laser at the time of emission. We "see" a moving spot, but what we're actually seeing is a progression of non-FTL arrivals. The photons carry information, but whatever knowledge is imparted at the point where the wall is illuminated is not transferred to any subsequently illuminated location.

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https://app.box.com/WitthoftResume Code: https://github.com/cellocgw

Re:I Think this article might be a bit misleading. by jbmartin6 · 2016-09-21 06:50 · Score: 1

Ah I see, thanks for that information.

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This posting is provided 'AS IS' without warranty of any kind, implied or otherwise.

Re:I Think this article might be a bit misleading. by hey! · 2016-09-21 07:13 · Score: 1

Again it's quibbling about what "sending a message" means.

To most people "sending a message" implies two roles: the sender knows the content of the message before it is sent, but the recipient does not know the contents until it is received. So if you say "you can use this machine to send a message", that's what they'll picture, but it's not what is happening here.

And if you say message sending is "faster than light", they simply extend this model, picturing something like the Ansibles of science fiction.

Here we have a situation that is completely unlike those ansibles. The information carrier is transferred at sub-light speeds, and the only reason we might say the information travels FTL is that we regard that carrier as being in an indeterminate state during transit.

--
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-21 07:17 · Score: 1

powerful laser aimed at a wall a few light-years away

or

sweep the laser beam along the wall's length

or

changes at several times the speed of light. But this is not information transfer

All this is clearly impossible (to accomplish, to validate, to even dream about being part of), but I get that you are using it as a way to facilitate the understanding.

On the other hand, I honestly don't see the practical implications (because this article deals precisely with the upcoming practical application of this theory) of anything you said. How could I? Your whole example cannot be validated, it happens what you say only because you say it.

You can create a theory to explain why a ball bounces up to certain height and then crosscheck your conclusions against a real scenario. The calculations might be a bit off, but at least they should show an acceptably good agreement with the real behaviour. Otherwise, what would be the point of the theory? Proving me that the ball actually has a different behaviour than the one I am seeing? Based on what? Shall I blindly trust a theory merely based on "I tell you so"?

Call me too practical if you wish, but I don't see too much value in a theory explaining something which I cannot crosscheck; a theory which seems to be mostly focused on solving problems created by itself. Remaining in the pure theoretical world forever is certainly an option, but should such a theory claim its practical applicability?

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 07:29 · Score: 1

Based on news like this we've heard in the past, though, transporting to Mars is just 10 years away.

And will continue to be for at least another 50 years.

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 07:32 · Score: 1

It seems to me that they could very well use it for ftl communications. If you can change the state of one particle to a state that represents either a 1 or 0...

That's just it; you can't do that.

You can only make measurements; you can't influence the result.

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 07:35 · Score: 1

They key can't be constructed until the participants have communicated over a classical (even public) channel to compare how they made their measurements. Until then, they sort of haven't opened the box with the cat in it.

I may have mixed my metaphors somewhere along the way...

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systemd is Roko's Basilisk.

Re:Explaining FTL non-information travel by wonkey_monkey · 2016-09-21 07:45 · Score: 3, Interesting

One could easily sweep the spot of a laser across the surface of the moon faster than a light-speed signal would do so.

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systemd is Roko's Basilisk.

Re: I Think this article might be a bit misleading by Anonymous Coward · 2016-09-21 07:52 · Score: 0

"I signed aboard this ship to practice medicine, not to have my atoms scattered back and forth across space by this gadget." - Admiral Leonard H. McCoy, MD

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-21 08:20 · Score: 1

I guess that you agree with the fact that doing anything from a years-light away position is (and will continue being for very long) impossible, immeasurable, invalidatable, etc., equivalently to what happens with other premises of that example. You might build a whole theory from it, but it would be a non-validated theory, a theory built on top of another theory. All the subsequent conclusions will have the same essence.

You might certainly draw conclusions from a non-validated theory, and more conclusions from those conclusions, etc. until reaching a point which you might actually validate. If you get there and you get proper results, assuming that the whole theory is fine might even be acceptable. But you have to actually validate it at some point, what means against the practically-measurable reality rather other part of the same theory.

I don't think that this experiment (or similar ones) represents this kind of validation. In any case, this wasn't my point; my point was: why relying on impossible examples to explain how practically useful a theory is? Can you use more realistic examples? Go ahead. Were the assumptions in your more-realistic examples drawn from elucubrations in other extremely-unrealistic examples? Same problem, then.

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-21 08:30 · Score: 1

PS: the speed of light is the fastest thing we know. Although it might be possible to go faster than that (why not? There is no solid justification for this being the absolute limit, other than our restricted perception and some old "I tell you so"s), no physical theory might defend such a thing (only an actual measurement could do it).

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re:Explaining FTL non-information travel by wonkey_monkey · 2016-09-21 09:27 · Score: 1

The impracticality of what the other guy suggested is neither here nor there; I posted my reply in protest, really, at your overly critical pedantry.

If you could do what he suggested, then the consequences would indeed be as he suggested. It's a thought experiment. It's meant to be an example, to help you understand the reality, not to prove something.

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systemd is Roko's Basilisk.

Re:Explaining FTL non-information travel by wonkey_monkey · 2016-09-21 09:31 · Score: 1

PS: the speed of light is the fastest thing we know. Although it might be possible to go faster than that (why not? There is no solid justification for this being the absolute limit, other than our restricted perception and some old "I tell you so"s)

The "solid justification" is that anything faster than the speed of light would, in some reference frame, be equivalent to travelling backwards in time, which would break causality - a property our universe seems to hold with without exception.

Furthermore, the speed of light constant. To all observers. You can never reach the speed of light because light always moves away from you... at the speed of light. If you fly away from Earth at half the speed of light, any light you see will still travel at the speed of light (and both you and Earth would agree on this, even though one of you is travelling faster than the other)

It very much is the limit. It isn't just "very fast." We can't even get close. Literally. No matter how fast you go, you're always travelling at 299 792 458 m / s below the speed of light. It's a fundamental property of our spacetime.

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-21 09:32 · Score: 0

If both parties are guaranteed to get the same information at the same time, then at least one piece of information has been shared faster than light: both parties know the moment at which the other party received the information.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 09:42 · Score: 1

Well, fine, if you want to think of it that way, go ahead, Pretty much every single physicist would say you're wrong, but what do they know, with their "degrees"...

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 09:47 · Score: 1

If both parties are guaranteed to get the same information at the same time

Not "at the same time."

then at least one piece of information has been shared faster than light: both parties know the moment at which the other party received the information.

No they don't. All that can infer is that if - and when - the other party measured the photon - and if nothing has disturbed it beforehand - they will get the same result. They won't actually know what happened until they compare notes classically.

The other party may have made their measurement a hundred years earlier, or a hundred years later, or even at a point in spacetime which can not be said to be either earlier or later (thanks to relativity).

No information passes from A to B, or from B to A.

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 09:48 · Score: 1

But you can't construct the key without communicating classically to collate your measurements. The key doesn't exist until that is done.

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by JesseMcDonald · 2016-09-21 09:53 · Score: 1

Thank you. That is exactly what I said.

The only part of quantum entanglement that is "instantaneous" (or "FTL") is that when one party performs its measurement, the wave functions for both of the entangled particles collapse out of their superimposed states simultaneously, no matter how far apart they might be. However, this does not communicate any information by itself; for that the two parties still need a classical channel. As you say, nothing is transferred FTL. An observer cannot tell that the wave function has collapsed without making a measurement, which would collapse the wave function anyway, and without a separate channel there is no way to know whether the other party observed the same quantum state.

--
"The state is that great fiction by which everyone tries to live at the expense of everyone else." - Bastiat

Re: I Think this article might be a bit misleading by K.+S.+Kyosuke · 2016-09-21 10:01 · Score: 1

Because HAL won't allow us to open the doors after they shut?

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Ezekiel 23:20

Re:I Think this article might be a bit misleading. by TechyImmigrant · 2016-09-21 11:34 · Score: 1

Well, fine, if you want to think of it that way, go ahead, Pretty much every single physicist would say you're wrong, but what do they know, with their "degrees"...

If you want to count the length of the procedure from the time the entities at both end perform and evaluation, then fine. But that's skipping over the time for the entangled photons to get from hither to thon.

All this yields is a shared private key. Of course some one has already unrolled a reel of fiber optic from hither to thon. You could have just let them transport the key in their pocket.

--
I should use this sig to advertise my book ISBN-13 : 978-1501515132.

Re:Explaining FTL non-information travel by Anonymous Coward · 2016-09-21 13:18 · Score: 0

I guess that you agree with the fact that doing anything from a years-light away position is (and will continue being for very long) impossible, immeasurable, invalidatable, etc., equivalently to what happens with other premises of that example.

Except it is measurable and practical in astronomy. Light echos from a supernova can look like a FTL phenomena until you realize it is a collision between a near planar light wave that is invisible until scattered our way, and a wide cloud of gas slightly askew such that there is a small time difference between scattered light from one end vs. the other. It also happens for some active radio galaxies where emissions come from collisions and shocks in plasma clouds. In all of those cases, what you see is a geometric point that appears to move FTL but is the result of things set in motion way earlier.

It is pretty similar to synchronizing a series of events by signals from a central location, which is also quite possible. There are plenty of experiments and situations that require synchronization within a nanosecond (in some specific frame...) but spaced more than a meter apart.

Re:I Think this article might be a bit misleading. by locofungus · 2016-09-21 18:22 · Score: 1

Sorry, I'm hopeless at explaining hence why I could never teach.

There aren't two identical "messages" in quantum teleportation. That would violate the no-cloning theorem. Instead there's one message that originally exists at point A and later exists at point B instead.

But - and this is the bit where it involves QM weirdness - there is no way to "read" a complete quantum state and record it classically. Think of it as a two bit word in a computer where every time you read one bit the reading circuit randomly disturbs the other bit.

QM teleportation lets us move that word from one place to another without changing either bit (but note that the original word (letter) is destroyed in the process.)

--
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-21 20:08 · Score: 1

I don't agree with your statements. I do fully agree with your underlying "causality may not be broken", but you are assuming many things which don't involve causality (just some old theoretical ideas. Only these old theories would break in case of finding faster-than-light anything; in fact, they are pretty fragile and can be broken in many different ways). Despite having a quite strong opinion on this specific front, I don't want to discuss about any of this. I am not trying to be rude or to assume anything about your particular behaviour, it is just not seeing the point in continuing (some past experiences together with the reality of "I don't really care/need to convince anyone").

By the way, I am perfectly aware about the speed of light value, as you can see in https://github.com/varocarbas/... (it is C#, but anyone should be able to understand this part of the code regardless of his programming background).

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-21 20:21 · Score: 1

I wasn't trying to be pedant, just realistic.

If you could do what he suggested, then the consequences would indeed be as he suggested

Why should I believe you? Based upon what? Upon you saying so or other person saying so? How can anyone be sure about the exact outputs under so uncertain conditions?

You can continue in the theoretical world for as long as you wish, but claiming that your theory has practical applicability is a different story.

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-21 20:58 · Score: 1

So, you are saying that it is possible to keep track of a specific event spread through a years-light distance?! It seems quite difficult to me to do such a thing (extremely unlikely to be even possible; and unpractically complex to be actually performed). But this isn't even the whole story in your example, the really big deal there is to perform certain action (laser hitting a wall) at such a distance?! We are talking about targeting a specific spot (no matter how big it is) which is so far away that it will take us years to see if it was actually hit?! And on top of all that, we have still to measure what is happening at such a distance, at the microscopic level!

You have to build a laser capable of targeting an object which is years-light away and also a device able to send you back information about the effects of the laser on that object?! Even by assuming that building such a technology is possible, we would be talking about each single attempt taking quite a few years to be performed! You have to send your analysis device many years before shooting the laser (whatever you will be using to send it would be much slower than the speed of light); or do you prefer to start building a device able to accurately measure what is happening light-years away, at the microscopic level?! Then, you would have to shoot the laser (the one you have built to hit a spot which is light-years far away). Then, you would have to wait more years for your device to send back the information. Even in the virtually impossible scenario of getting everything right on the first attempt, it would take you loooots of years to do just one of these experiments by assuming that you have access to what seems sci-fi technology. How can you say that this is practically doable?

As said in my other message, I am not trying to be pedantic but a so extremely-unrealistic example should never be used to support practical applicability. It is a theoretical scenario, built over theoretical ideas which merely have theoretical applicability. Eventually, you can draw some abstract conclusions which might be somehow useful in a real scenario; but expecting a very specific result to happen by taking it as the sole reference is very naive, faulty, non-scientific, etc.

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re:Explaining FTL non-information travel by wonkey_monkey · 2016-09-21 21:15 · Score: 1

By the way, I am perfectly aware about the speed of light value

Jesus. Stop acting so righteously offended. I wasn't being condescending. I wrote it out because I wanted to avoid saying "at the speed of light below the speed of light," that's all.

Despite having a quite strong opinion on this specific front, I don't want to discuss about any of this. I am not trying to be rude or to assume anything about your particular behaviour, it is just not seeing the point in continuing (some past experiences together with the reality of "I don't really care/need to convince anyone").

Then perhaps you should just keep quiet instead of starting arguments if you have no intention of concluding them.

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systemd is Roko's Basilisk.

Re:Explaining FTL non-information travel by wonkey_monkey · 2016-09-21 21:16 · Score: 1

Why should I believe you? Based upon what? Upon you saying so or other person saying so? How can anyone be sure about the exact outputs under so uncertain conditions?

Again, you are being too pedantic. Is there, possibly, some hitherto unknown physical phenomena that would stop the suggested idea working? Well, if there is, it has never shown itself.

Pulsars do the equivalent of what was suggested all the time. They are thousands of light years away, and they are sweeping signals around the entire 360 degrees of their view of the universe in fractions of a second. We've seen nothing interfering with them, so there is absolutely no reason to assume that the OP's thought experiment wouldn't work. But even that is missing the whole point.

You can continue in the theoretical world for as long as you wish, but claiming that your theory has practical applicability is a different story.

Gah! Once again, it is not about practical applicability. The OP was trying to give an example, a thought experiment, to help you understand. But you seem hell-bent on throwing his helpfulness in his face.

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systemd is Roko's Basilisk.

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-21 21:36 · Score: 1

Gah! Once again, it is not about practical applicability. The OP was trying to give an example, a thought experiment, to help you understand. But you seem hell-bent on throwing his helpfulness in his face.

OK. Sorry, this wasn't my intention, neither being pedantic. I apologise for the misunderstanding. All clear now.

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-21 21:45 · Score: 1

Then perhaps you should just keep quiet instead of starting arguments if you have no intention of concluding them.

My intention wasn't starting anything (not outside the theoretical/practical applicability of QM), but I see the problem now. Sorry (I do understand that my attitude of not wanting to discuss further isn't precisely ideal), I will try to avoid these situations in the future.

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re:I Think this article might be a bit misleading. by wonkey_monkey · 2016-09-21 21:53 · Score: 1

when one party performs its measurement, the wave functions for both of the entangled particles collapse out of their superimposed states simultaneously, no matter how far apart they might be.

I'm not sure that can be said to be true. There is no definite "simultaneously" for spatially separated objects.

If one person makes a measurement, then the other's state will have been collapsed. But I don't think you can make any statement about when it happened.

I know there have been experiments that put an lower limit of so many thousand times the speed of light on it, but I'm not really sure such numbers make proper sense.

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systemd is Roko's Basilisk.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-22 02:03 · Score: 0

From the text at the end it sounds like they have 3 people in a row: Alice, Charlie and Bob (in that order). Alice and Bob send particles to Charlie at light speed I assume. Charlie does the magic to cause teleportation and Bob gets the data Alice wanted to send. Assuming Charlie sits half way between Alice and Bob wouldn't that give a transmission speed of 2c? Because the particles still need to travel half the way and then the information is teleported where they meet.

Not instant communication but achieving 2c is still impressive. If that is what they actually did.

Re:I Think this article might be a bit misleading. by Anonymous Coward · 2016-09-22 02:04 · Score: 0

the state of the particle could be used as information though, couldn't it? if we can recognize 2 different states of the particle consistently, then you can send binary data via the particle itself.

Re:Explaining FTL non-information travel by Anonymous Coward · 2016-09-22 02:32 · Score: 0

Why do you keep insisting on doing this over light years? A dental tool at 300k rpm and a mirror can easily sweep a dot faster than light at 10 km. Or just simply having a standard 10 ns pulsed laser hit a 10 ft wall at an angle, and using a cheap oscilloscope can get the same effect. Or for more money, use an off the shelf ps laser and gated camera to see the dot move across the wall with images, which is actually a practical method used by a variety of labs for high speed imaging.

The effect is very simple and practical to perform. Concentrating on particular numbers picked to illustrate the point and make the math easy is missing the seeing a tree and missing the forest. Your complaints are on par with a story Feynman used where a person tries to get out of a speeding ticket for going 60 mph in a 30 mph zone, because it is impossible for them to go 60 mph if they have been traveling less than an hour.

Re:Explaining FTL non-information travel by CustomSolvers2 · 2016-09-22 04:00 · Score: 1

Why do you keep insisting on doing this over light years

Because this is what you used in your original example; the one which I said that was completely unrealistic.

A dental tool at 300k rpm and a mirror can easily sweep a dot faster than light at 10 km

I am afraid that nothing can go faster than light (well... my ideas on this front are a bit more complex than that. If you read my comments to the other person in this subthread, you would understand why I don't want to go deeper in that direction).

Feynman used where a person tries to get out of a speeding ticket for going 60 mph in a 30 mph zone, because it is impossible for them to go 60 mph if they have been traveling less than an hour.

Not sure what this joke (?!) has to do with trying to apply the conclusions from an impossible-to-be-reproduced example to another situation which is different by lots of orders of magnitudes (the expression orders of magnitude seems to have virtually no meaning here; talking about extrapolating light-years conclusions to what a dental tool can deliver). Are you aware about the surprisingly limited applicability of all our physical knowledge? Do you know that a model built on "particular numbers" is only applicable for numbers not too far away from that range? That all our theories aren't more than very simplistic summaries of what our limited understanding can guess under very specific conditions?

Anyway, I don't see the point of continuing with all this. We clearly see things in very different ways and this discussion will not change that fact. Thanks for being so nice and sorry if any of my comments bothered you.

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re: Explaining FTL non-information travel by Anonymous Coward · 2016-09-22 08:10 · Score: 0

Nothing can go faster than light, but you can create the illusion of something going faster than light when given enough time before hand for synchronization with slower than light communication, which has been the whole discussion here (which includes multiple ACs with parallel examples, but all unified by that point).

As far as saying a model is good at only certain numbers ,you're doubly wrong here. First off, this isn't a model, but basic geometry that is pretty scale invariant. Second, the effects have been well observed on scales from millimeters in optical experiments to thousands of light years with AGN jets.

Pedagogical examples tend to be simplified, but that doesn't make them impractical or unverifiable when it turns out very similar things have been done and observed in a broad number of cases where the "hidden" details are irrelevant to the principle being illustrated.

Re: Explaining FTL non-information travel by CustomSolvers2 · 2016-09-22 09:02 · Score: 1

I don't agree with most of what you say, but again I don't see the point of continuing this discussion. So, better stopping it here.

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Custom Solvers 2.0 = Alvaro Carballo Garcia = varocarbas.

Re: I Think this article might be a bit misleading by Methadras · 2016-09-22 12:02 · Score: 1

I, for one await my BrendleFly overlord.

Re: I Think this article might be a bit misleading by Anonymous Coward · 2016-09-22 13:21 · Score: 0

You are correct sir. With this process a quantum encrypted message will corrupt if someone attempts to read it. Also this has implications on what quantum particles really are. I do so hope they rest even more on this subject matter. We've already brought an orwellian type narrative to center stage. Let's not muck about and bring a Gordon Freeman style Armageddon epic to stage left. More testing. Transparency, respect, and mindfulness are three priority protocols to adhere to. This is a major responsibility as well as a gift. Quantum computing will open many doors. In health, banking, analytics will all see a major bound. The start up companies appear to have plenty of time to compete and develop with the big boys like hp. I've noticed a shift in hp's focus lately. My only thoughts are quantum linked terminals. SaaS. Well we will just have to wait and see. Like always..... I've known about this for years now. Been waiting to enter cyberspace at a crisp -37c for seven years. Been wanting to talk and hear about it that long too. And not a scientific discussion, mind you, but more a human discussion where people can express their wonder. Now some of us can return to saying phrases like, "i don't know how it works i just fix em ma'am."

Re:Explaining FTL non-information travel by RespekMyAthorati · 2016-09-23 09:26 · Score: 1

No you can't.
If you try sweeping the beam, you will see the spot on the moon stay where it was for 2.6 seconds (1.3 light seconds each way), then move to the next position.
A 2.6 second delay is not "faster than light", it is exactly what you would expect with light travelling at c.

Re:Explaining FTL non-information travel by wonkey_monkey · 2016-09-23 09:48 · Score: 1

You've missed the point.

then move to the next position.

It (the spot) will "move" from the initial position to that "next position" faster than a light-speed signal could do so over the surface of the Moon.

Forget the delay. Just imagine that someone else is sweeping the laser pointer and you're just watching the result, so any delay from the Earth to the Moon is of no interest to you - in fact, maybe you don't even know it's someone on Earth doing it. What you would see is a spot "moving" across the surface of the Moon apparently faster than the speed of light.

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systemd is Roko's Basilisk.

Re:Explaining FTL non-information travel by RespekMyAthorati · 2016-09-23 11:20 · Score: 1

The "solid justification" is that anything faster than the speed of light would, in some reference frame, be equivalent to travelling backwards in time, which would break causality

Which means nothing, since causality can only be determined in the reference frame where the action (i.e. the acceleration) is occurring.
The fact that causality may appear to be broken from some other reference frame is all very interesting, but ultimately irrelevant.

Re:Explaining FTL non-information travel by wonkey_monkey · 2016-09-23 23:53 · Score: 1

Which means nothing, since causality can only be determined in the reference frame where the action (i.e. the acceleration) is occurring.

Yes, exactly. That was the whole point of bringing this up in the first place, as per the top-level post:

My favorite way to explain the difference between something "happening" FTL and useful information not being able to travel FTL is this:

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systemd is Roko's Basilisk.

Re:Explaining FTL non-information travel by wonkey_monkey · 2016-09-23 23:56 · Score: 1

Sorry, ignore my other post. I could some confused idea about what you were replying to.

The fact that causality may appear to be broken from some other reference frame is all very interesting, but ultimately irrelevant.

It's not that it may appear to be broken, it's that it would be broken.

If something could travel faster than light in one reference frame, then it would, literally, be travelling backwards in time in some other reference frame. It's an inescapable and proven consequence of how spacetime is divided into space and time differently by different observers.

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systemd is Roko's Basilisk.

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Quantum Teleportation Achieved Over 7km of Cable (sciencealert.com)

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