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ETpro's avatar

What is the speed of action of quantum entanglement over distance? (Strange Universe series)

Asked by ETpro (34145 points ) December 10th, 2010

When subatomic particles interact, they gain something called quantum entanglement. You cannot fully describe one member of a quantum entangled group without describing all its members. This is true even when the entangled members of the group are spatially separated. If, for instance, you measure the spin of one electron and thus collapse its wave-state, you simultaneously collapse the wave-state of all its quantum entangled partners even without having measured them. The question is, if the individual members of the quantum entangled group are widely separated, how long does it take for the effect to pass from one to another. At what speed does quantum entanglement propagate?.

This is a continuation in the Strange Universe series.
1—If Space is emptiness, what does gravity grab to bend it?
2—If photons have no mass, why are they affected by gravity?
3—What does it take to convert energy into mass?
4—How does the universe impose its fractal-like patterns of order on chaotic systems?
5—How small can the repetitive fractal features of nature get?
6—How can the most distant quasar be 28 Billion light years away?
7—Can nothing exist without the Universe?
8—How can order emerge out of chaos?
9—Where is the center of the Universe?
10—If CERN proves there are parallel universes, will you move?
11—If the universe expands at faster than the speed of light, does it begin to go back in time?
12—What is the expanding universe expanding into?
13—Big Bang Theory—How can you divide infinity into a single finite whole?
14—How would you answer this speed-of-light question?
15—What happens when the expansion of the Universe reaches the speed of light?
16—What’s your Strange Universe example to illustrate Sir Arthur Eddington’s quote?

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20 Answers

Rarebear's avatar

It’s instantaneous.

ETpro's avatar

@Rarebear That’s pretty darned fast. How do you reckon that works?

phoebusg's avatar

@Rarebear what is your source? My guess is that we’ll find out as soon as we develop the first quantum computer architecture – and then transmit stuff over. I read that there’s still a very big error chance, and the system becomes unstable/unusable. Latest development was from an Australian team making a more fault-tolerant design.

ETpro's avatar

@phoebusg Read up on the problems that the difficulties in actually building a quantum computer that does anything meaningful. There are numerous gotchas inherent in the process, where we would end up with time paradoxes that make many operations impossible, or where you can get a result, but you can’t at the same time know what it means. But I do believe we will overcome these.

wundayatta's avatar

I had heard it was supposed to be instantaneous, too.

But how is this related to Quantum computing?

ETpro's avatar

@wundayatta If you could use quantum entangled particles as the switches in a computer, and they could be flipped instantaneously so input and output took zero time no matter how many nodes the computation had to cycle through, that would be one fantastic computer. We have statistical analysis problems now that take months to calculate of a very expensive super computer. Imagine being able to get the answer instantaneously.

CaptainHarley's avatar

Faster than lightspeed, although whether this means “istantaneous” has still to be determined.

ETpro's avatar

@CaptainHarley Amazingly, the fact that the action is instantaneous over substantial spacetime has been demonstrated and verified experimentally.

CaptainHarley's avatar

Are you referring to the Aspect experiments?

ratboy's avatar

At least 10,000c?

ETpro's avatar

@CaptainHarley I was talking about the 2008 Quantum Entangled Images experiment.

@ratboy, That would be pretty close to instantaneous, but distinguishable from it.

CaptainHarley's avatar

That’s one with which I am unfamiliar. Guess I’ve not kept up with that these past few years. Sorry!

PhiNotPi's avatar

I would say instantly. I one expirament, scientists took two entangled (I think photons) about five miles apart, and when they flipped the state of one photon, the other photon flipped too, and the time difference between the two events was several times faster than the time that light would take to travel between the two points.

Paradox's avatar

@ETpro Actually Rarebear is correct or pretty darn close to it according to an experiment used to verify a theoretical expectation. Alain Aspect’s team confirmed non-locality to be instantaneous or at least close to it (many times faster than light speed). I believe they did an experiment using “excited” caesium atoms which means that an electron has been given excess energy that it retains for a while by existing in a larger orbit. The electron is unstable and drops in orbit shedding its excess energy. The electron has “decayed” and its lost energy is expelled as a pair of photons travelling in diametrically opposite directions in wavy lines. The “polarisation” of the photons was indicated by the direction of the electrical potential waveform. When one of the photons hit an angled polarising filter they used, to change the polarity, the partner wave flipped at the same instant regardless of the separating distance.

I found this out from reading one of my books on quantum mechanics. I personally like this finding because it supports the ECM theory that seeks to unite Einstein’s relativity theories with QED. ECM seems very strong mathematically to me but the theory is not well known. Dam I’m having trouble with my internet connection again.

CaptainHarley's avatar

If you want to stretch your mind and deal with something rather esoteric, read up on the E8 “geometric theory of everything.” Talk about mind-bending! [ cf Scientific American magazine, December 2010 ]

Rarebear's avatar

@phoebusg That’s the reason why Einstein was so uncomfortable with quantum mechanics was it’s “Spooky action at a distance.” The issue is that normally things communicate by some sort of force boson, such as a photon, or gluon, which moves, at the fastest, the speed of light. Quantum entanglement happens instananeously, which is why Einstein was so uncomfortable.

From Wikipedia,

Theories involving hidden variables have been proposed in order to explain this result. These hidden variables would account for the spin of each particle, and would be determined when the entangled pair is created. It may appear then that the hidden variables must be in communication no matter how far apart the particles are, that the hidden variable describing one particle must be able to change instantly when the other is measured. If the hidden variables stop interacting when they are far apart, the statistics of multiple measurements must obey an inequality (called Bell’s inequality), which is, however, violated both by quantum mechanical theory and experimental evidence.[citation needed]

ETpro's avatar

@Paradox, they seem to act instantaneous.

@CaptainHarley Found this cool article on E8 Geometric theory of everythingl

@Rarebear Thanks. This seems the perfect proof of the claim that “The Universe Is Stranger than you can imagine”

mattbrowne's avatar

Another word is infinite.

The speed is infinite.

Infinity is part of nature.

There’s an infinite amount of real numbers between 1 and 2 for example. And we can’t even start counting them.

ETpro's avatar

@mattbrowne Infinite speed. My god man, do you have any idea how dangerous that is?> Why that’s one step beyond ludicrous speed.

mattbrowne's avatar

@ETpro – Oh, yeah… makes the Enterprise look like a snail.

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