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Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

extremetech.com

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Re: Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

#21

Post by sbashyal »

oneandoneis2 wrote: post #18

> One half of the pair was then observed, and the time for the other half to assume the same state is measured. How?? How is it possible to observe whether or not an entangled particle has had its state resolved by the other particle being observed?

In a pair of quantum particles [1], when one is spinning-up, other is spinning down even when they are separated. Therefore it is possible to find out about the state of one by looking at the other.

[1] http://en.wikipedia.org/wiki/Quantum_entanglement#Concept

Re: Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

#23

Post by lnanek2 »

oneandoneis2 wrote: post #18

> One half of the pair was then observed, and the time for the other half to assume the same state is measured. How?? How is it possible to observe whether or not an entangled particle has had its state resolved by the other particle being observed?

Well, for entangled light, figuring out the path taken by one part of the pair forces both to produce no interference patterns. Their superpositions both collapse into a set state. I assume there's a similar effect for electron deflection or whatever they are using. Electron beams can similarly produce interference patterns.

Re: Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

#24

Post by mdda »

a_p wrote: post #11
jivatmanx wrote: post #7

The speed of light ought to be enough for anyone.

It's not fast enough for high frequency traders. That's why all the major HF traders pay large sums of money to rent space for their servers at the site of the exchanges.

I thought that HF traders are just paying to be faster than their competitors. If the exchange servers had a 1 mile (or 10ms, or whatever) exclusion zone around them, everyone would be huddling up against that instead.

Re: Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

#25

Post by fjorder »

ars wrote: post #16

How does this rule out hidden variables? I am aware of Bells inequality, but how do they show that for this specific experiment there were no hidden variables in play?

They test a CHSH Bell inequality in this paper. This rules out local hidden variable theories. Non-local hidden variable (NLHV) theories are another matter entirely. Indeed, some NLHV theories may reproduce the predictions of quantum theory exactly.

Re: Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

#26

Post by colanderman »

sbashyal wrote: post #21
oneandoneis2 wrote: post #18

> One half of the pair was then observed, and the time for the other half to assume the same state is measured. How?? How is it possible to observe whether or not an entangled particle has had its state resolved by the other particle being observed?

In a pair of quantum particles [1], when one is spinning-up, other is spinning down even when they are separated. Therefore it is possible to find out about the state of one by looking at the other. [1] http://en.wikipedia.org/wiki/Quantum_entanglement#Concept

Yes but doing so collapses the wavefunction. Hence there's no way to observe when the wavefunction collapses.

Re: Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

#27

Post by fjorder »

Contrary to the claims of the extremetech article, they have not closed all loopholes in this experiment. Specifically, the detection loophole has not been closed. This loophole is caused by not being able to detect a high enough portion of the photons your source emits. A paranoid person might argue that the ones you do detect are not a representative sample. For example, some devious third party could be choosing which photons you detect in such a way that your results are skewed. Yes... This is a paranoid suggestion, but closing loopholes is all about satisfying the paranoid.

In this paper they invoke the assumption of "fair sampling". i.e. They assume what they do detect is representative. Ergo, they have not closed the detection loophole in this experiment. Fair sampling is a perfectly reasonable assumption to make and is very commonly used, so this should not be interpreted as invalidating their results. It just leaves room for improvement in the future, since single photon detectors with sufficient efficiency to close the detection loophole do now exist (They are very bleeding edge).

Note that the paper is correct and does not make the claim that "all loopholes" have been closed. The extremetech article got it wrong.

Re: Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

#28

Post by OGinparadise »

jerf wrote: post #2

"If it turns out that we actually can communicate data via quantum entanglement, we now know that it’ll be much faster than the speed of light." No, no, no, no, no. No. No. No. Quantum entanglement can not be used to communicate in that manner, on its own. This is well-established, and given the how mathematical the establishment is, it's not going to change anytime soon. No. No. No. Stop that. No.

But the title leads people to click. Why let about the little details like truth and math interfere with that?

Re: Einstein’s ‘spooky action at a distance’: 10,000 times faster than light

#30

Post by Raz0rblade »

It is so simple, this is the same object seen over 2 places. Think of a fishing tank, the side glass wall and the front glass wall show the same fish. And that's i hope an easy to understand example of an extra dimension, it solves many physics problems add a dimension.. As the fish swims in the tank, both walls show change in position to and no need for communication at all, its just one fish.

you need proof for extra-dimensional existence just take all those experiments that could be solved by it .. double split... spooky action .... and many more.. (even quantum computers inner working)

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