Quantum entanglement breakthrough

[Perspicuo]

Teleportation Is Real and Here’s Why it Matters
http://time.com/2800071/teleportation-quantum-entanglement/

The point is, the Delft researchers proved the principle by isolating target entangled electrons inside two supercooled diamonds placed 10 meters—or 33 ft.—apart, creating what one of the physicists described as “miniprisons” for them. They then maniupulated their spin rate and determined that the behavior of one indeed continued to determine the spin of the other, and vice versa, even at that distance. Something similar had been achieved before, in 2009, by University of Maryland researchers, but the experiment worked only one out of every 100 million attempts. This one succeeded 100% of the time. Next, the Dutch plan to expand their work—literally—trying to see if the quantum entanglement holds at a distance of 1 kilometer, or .62 mi.

 

[Perspicuo]

Also reporting:
CNET: Scientists achieve reliable quantum teleportation for first time
http://www.cnet.com/news/scientists-achieve-reliable-quantum-teleportation-for-the-first-time/

Researchers at Delft University of Technology.

 

[ryan]

So... I have a friend who doesn't understand what is going on in the experiment but understands the basic concept of entanglement. Can anyone explain this so that I he will understand?

 

[Juma]

Teleportation Is Real

In what way is this teleportation?

 

[Kharakov]

Teleportation Is Real

In what way is this teleportation?

It's teleportation of information. In other words, information is transmitted without passing through space.

The information transfer is instantaneous, instead of taking place at the speed of light or slower. Information doesn't pass through space at greater than c without entanglement or telepathy.

 

[bilby]

I have a more efficient way to communicate over a distance of 10 metres; I call it 'shouting'.

 

[Kharakov]

what?


Hey, so what would you call communicating through a period of time, instead of a distance in space?

 

[Juma]

Teleportation Is Real

In what way is this teleportation?

It's teleportation of information. In other words, information is transmitted without passing through space.

The information transfer is instantaneous, instead of taking place at the speed of light or slower. Information doesn't pass through space at greater than c without entanglement or telepathy.

When and where was it shown that information is transported faster than c?

 

[Narapoia]

Teleportation Is Real

In what way is this teleportation?

It's teleportation of information. In other words, information is transmitted without passing through space.

The information transfer is instantaneous, instead of taking place at the speed of light or slower. Information doesn't pass through space at greater than c without entanglement or telepathy.

When and where was it shown that information is transported faster than c?

Second the question, I was of the understanding that this is impossible with our current understanding of physics - would love to see it proved wrong though.

 

[fromderinside]

That's nice. Something determined remains determined over time and space. Fascinating discover that.

 

[dystopian]

Second the question, I was of the understanding that this is impossible with our current understanding of physics - would love to see it proved wrong though.

Scientists have already demonstrated that quantum entanglement effects propagate at a speed of *at least* 10.000 times the speed of light. http://www.extremetech.com/extreme/...stance-at-least-10000-times-faster-than-light

To my understanding, it was previously considered questionable that such experiments transmitted any actual information; but information was most definitely transmitted/teleported in the Delft study; and they can do it reliably, which is a huge step. Of course, you can say that it hasn't been demonstrated that this was done faster than the speed of light like the Chinese did, and that maybe there's some sort barrier in place that would cause the experiment to break down when they try it. But then, that's exactly what this is all leading up to; getting the proof that some of our physics understanding is wrong.

 

[skepticalbip]

Teleportation Is Real and Here’s Why it Matters
http://time.com/2800071/teleportation-quantum-entanglement/

The point is, the Delft researchers proved the principle by isolating target entangled electrons inside two supercooled diamonds placed 10 meters—or 33 ft.—apart, creating what one of the physicists described as “miniprisons” for them. They then maniupulated their spin rate and determined that the behavior of one indeed continued to determine the spin of the other, and vice versa, even at that distance. Something similar had been achieved before, in 2009, by University of Maryland researchers, but the experiment worked only one out of every 100 million attempts. This one succeeded 100% of the time. Next, the Dutch plan to expand their work—literally—trying to see if the quantum entanglement holds at a distance of 1 kilometer, or .62 mi.

Was there a peer reviewed paper on this published (I can't get the linked Time article to open to see if they referenced one) or was it just released to the mass media like the "cold fusion" report by Fleischmann–Pons? Or like the media release by (I think it was Italian) researchers a couple years ago that had detected FTL particles - at least they were FTL until they found a bad connection on their test equipment.

If what they seem to say is true and not measurement error then it is an amazing discovery. My understanding is that, if you change the quantum state of one entangled particle, entanglement is broken - it doesn't affect the other particle.

 

[dystopian]

Was there a peer reviewed paper on this published (I can't get the linked Time article to open to see if they referenced one) or was it just released to the mass media like the "cold fusion" report by Fleischmann–Pons?

I found a reference in some other article saying they published their results in Science on may 29th.

edit: http://www.sciencemag.org/content/early/2014/05/28/science.1253512

 

[Juma]

Second the question, I was of the understanding that this is impossible with our current understanding of physics - would love to see it proved wrong though.

Scientists have already demonstrated that quantum entanglement effects propagate at a speed of *at least* 10.000 times the speed of light. http://www.extremetech.com/extreme/...stance-at-least-10000-times-faster-than-light

To my understanding, it was previously considered questionable that such experiments transmitted any actual information; but information was most definitely transmitted/teleported in the Delft study; and they can do it reliably, which is a huge step. Of course, you can say that it hasn't been demonstrated that this was done faster than the speed of light like the Chinese did, and that maybe there's some sort barrier in place that would cause the experiment to break down when they try it. But then, that's exactly what this is all leading up to; getting the proof that some of our physics understanding is wrong.

So the answer is that it hasnt been shown yet. Pity.

 

[Kharakov]

There is also the fact that even if entanglement (and thus information transfer) can be achieved over vast distances, the set up requires light speed or slower transport of the entangled particles, unless one can use previously entangled particles to do the setup.

In other words, the particles are entangled first (store information about the state of both particles), placed where they are desired, and then information is transferred "faster than light".

 

[PyramidHead]

In practice, how would this work? Would a person on one end of the entangled particle pair be able to flip the spin in some way that corresponds to e.g. Morse code, which would then be interpreted by the other side?

How would this change the outcome of various thought experiments that illustrate the unbreakable barrier of lightspeed in transmitting info (the Twin Paradox, for instance)? Would one twin be able to "text" the other while accelerating?

Just speculating. I know nothing about QM.

 

[skepticalbip]

There is also the fact that even if entanglement (and thus information transfer) can be achieved over vast distances, the set up requires light speed or slower transport of the entangled particles, unless one can use previously entangled particles to do the setup.

In other words, the particles are entangled first (store information about the state of both particles), placed where they are desired, and then information is transferred "faster than light".

That is essentially Einstein's criticism of the Copenhagen interpretation.

Seperate a pair of entangled particles by a light year then if you identify the one that stayed behind with a quantum state of say spin up you would immediately know that the other is spin down. The Copenhagen interpretation would have us understand that the knowledge of that second particle's spin state crossed the light year instantaniously. I kinda liked Einstein's analogy of doing the same with a pair of gloves to determine if the one a light year away was a left or right hand glove.

 

[PyramidHead]

There is also the fact that even if entanglement (and thus information transfer) can be achieved over vast distances, the set up requires light speed or slower transport of the entangled particles, unless one can use previously entangled particles to do the setup.

In other words, the particles are entangled first (store information about the state of both particles), placed where they are desired, and then information is transferred "faster than light".

That is essentially Einstein's criticism of the Copenhagen interpretation.

Seperate a pair of entangled particles by a light year then if you identify the one that stayed behind with a quantum state of say spin up you would immediately know that the other is spin down. The Copenhagen interpretation would have us understand that the knowledge of that second particle's spin state crossed the light year instantaniously. I kinda liked Einstein's analogy of doing the same with a pair of gloves to determine if the one a light year away was a left or right hand glove.

But suppose a certain datum of information like "it is raining in Brooklyn" was encoded by the combination "left left right left right right left" or something. The person who had to travel in a rocketship to the location of the other particle may know ahead of time that the spin would always be the opposite of the particle on Earth, as well as the linguistic code for interpreting a sequence of spins, but she wouldn't necessarily know the information that was encoded.

 

[Kharakov]

Note that the information "transferred" is not something that can be controlled. When one observes the left glove, one knows the state of the other glove. One doesn't pick the glove, which means one doesn't get to pick the information that the other observer detects.

 No-communication theorem

 

[Bomb#20]

Was there a peer reviewed paper on this published (I can't get the linked Time article to open to see if they referenced one) or was it just released to the mass media like the "cold fusion" report by Fleischmann–Pons?

I found a reference in some other article saying they published their results in Science on may 29th.

edit: http://www.sciencemag.org/content/early/2014/05/28/science.1253512

There's no indication in the abstract that they achieved teleportation of information supplied by the experimenters. This appears to be an evolutionary step toward quantum computers, not a breakthrough step toward faster-than-light communication. Based on all previous teleportation/entanglement experiments, the information that's teleported, if we even want to call it that, has to be generated randomly by a quantum measurement at one site in order to be received at the other site. So there's no way you can modulate the "signal" in order to send a message -- the guy at the receiving end can't tell the difference between the "data" he receives and white noise unless he compares notes with you after the fact, using a speed-of-light channel. The Delft experiment appears to be more of the same: interesting new technology, but no new physics.