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Quantum entanglement shows that reality can't be local

arstechnica.com

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Re: Quantum entanglement shows that reality can't be local

#41

Post by Osmium »

ecliptic wrote: post #35
MBlume wrote: post #24

Earlier quoted context omitted.

Nope. Pushing on the end of the beam sends a pressure wave through the beam. The button gets pushed when the wave reaches the other end. Wave travels significantly slower than light.

If you push on the beam and the other end does not move right away doesn't that imply that the beam has compressed and is not rigid?

What you're proposing is an effect mediated by physical forces. Specifically, on a fundamental, atomic level your beam is made up of atoms. And when you push it, you're bringing atoms closer together, that feel an electrostatic repulsion. And the beam moves.

So, in the best case, this method of communication is equivalent to communicating with electromagnetic waves. And they have a speed limit: the speed of light :)

So this wouldn't be faster than light communication.

Re: Quantum entanglement shows that reality can't be local

#42

Post by [deleted] »

ecliptic wrote: post #35
MBlume wrote: post #24

Earlier quoted context omitted.

Nope. Pushing on the end of the beam sends a pressure wave through the beam. The button gets pushed when the wave reaches the other end. Wave travels significantly slower than light.

If you push on the beam and the other end does not move right away doesn't that imply that the beam has compressed and is not rigid?

[deleted]

Re: Quantum entanglement shows that reality can't be local

#43

Post by [deleted] »

ecliptic wrote: post #35
MBlume wrote: post #24

Earlier quoted context omitted.

Nope. Pushing on the end of the beam sends a pressure wave through the beam. The button gets pushed when the wave reaches the other end. Wave travels significantly slower than light.

If you push on the beam and the other end does not move right away doesn't that imply that the beam has compressed and is not rigid?

[deleted]

Re: Quantum entanglement shows that reality can't be local

#44

Post by cs702 »

I've always found classical Newtonian physics, the Special Theory of Relativity, and (to a lesser extent) the General Theory of Relativity to be understandable at an intuitive level, but quantum phenomena just baffles me, even when I think I "understand" it.

PS. IvoDankolov: I find it difficult or impossible to think intuitively about quantum phenomena.

Re: Quantum entanglement shows that reality can't be local

#45

Post by IvoDankolov »

MBlume wrote: post #27
nessus42 wrote: post #23

This article completely ignored the Many Worlds Interpretation, which preserves all of realism, locality, and Relativity.

Yeah. It shouldn't be that surprising that when you arbitrarily assume that part of the wavefunction magically disappears sometimes, you get weird results like non-locality.

It's always amusing to see the kind of excuses that pop up when you try to explain entanglement or interference in the mindset of wavefunction collapse.

I'm still not entirely sure why so many people consider collapse to be simpler. Is it too daunting to think of the world as an amplitude distribution that propagates in a way that we're not intuitively used to? Too hard to think of ourselves as part of quantum mechanics, because that thing I see there on the measuring device must be the reality, damn it, and what the hell do you mean I've just entangled myself and the device along with the system?

Or maybe just tradition and accepting the "scripture" coming from the established authority. How could we best test that?

Re: Quantum entanglement shows that reality can't be local

#46

Post by [deleted] »

fixermark wrote: post #4

One thing I've never understood about interpretation of quantum entanglement experiments: Based on what I've learned of these experiments, it seems to me that the least mind-bending interpretation is that the entanglement event results in two particles that have some complementary property k (i.e. one particle has k and the other has ~k) and which one of the two, k or ~k, is had by one of the particles is unknowable…

[deleted]

Re: Quantum entanglement shows that reality can't be local

#48

Post by ars »

ecliptic wrote: post #35
MBlume wrote: post #24

Earlier quoted context omitted.

Nope. Pushing on the end of the beam sends a pressure wave through the beam. The button gets pushed when the wave reaches the other end. Wave travels significantly slower than light.

If you push on the beam and the other end does not move right away doesn't that imply that the beam has compressed and is not rigid?

> doesn't that imply that the beam has compressed and is not rigid?

Yes it does. And in fact that is the case: The beam has compressed. A fully rigid beam is impossible.

Re: Quantum entanglement shows that reality can't be local

#49

Post by ars »

MBlume wrote: post #30
nessus42 wrote: post #25

Earlier quoted context omitted.

Relativity says that you can't construct a rigid beam 25 million miles long.

I think that's going a little too far. If you can construct a "rigid beam" five feet long, I see no way that relativity countermands a "rigid beam" 25 million miles long. It's just that "rigid" doesn't mean what grandparent thinks it means -- info still travels through the beam via pressure waves.

> If you can construct a "rigid beam" five feet long

Except you can't. A existence of sound traveling through the beam proves without a doubt that the beam is not rigid.

Re: Quantum entanglement shows that reality can't be local

#50

Post by klodolph »

ChuckMcM wrote: post #3

This is for me the most interesting part of the whole teleportation / entanglement research. When these papers started coming out we debated the notion of 'faster than light' communication. The counter argument was that you had to move the particles apart and that was constrained by the speed of light. Then the question of "when" the state was resolved was pondered. There were two thought experiments proposed at this…

> short story about someone doing this and discovering that it was the galactic equivalent of 'shortwave' radio and have the alien equivalent of the FCC come out to the planet to arrest the scientists for transmitting without a license

"Fine Structure" -- bits of a soft-SF story you can read online http://qntm.org/structure http://everything2.com/?node=fine+structure

It's of varying quality, I think people usually link to "Oul's Egg" first because it's one of the best sections.

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