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How Bell’s Theorem proved ‘spooky action at a distance’ is real

quantamagazine.org

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Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#111

Post by AnimalMuppet »

themgt wrote: post #16
nobodyandproud wrote: post #11

Earlier quoted context omitted.

Those objections to super determinism seem weak, or more along the lines of “I don’t like the implications, so I won’t consider it.” Genuine question: Would quantum computers work in any deterministic framework?

I've quoted it before but I will again just because I hate superdeterminism so much: First, the logical flow: Bell’s theorem proves that no local, realistic theory can reproduce the predictions of quantum mechanics. It does so by considering a very specific situation of entangled particles being measured by spin detectors set at different angles. Critically, the angles of these spin detectors are assumed to be set in…

> I can only reply that yes, it’s possible. I cannot prove it wrong. But I can find it unreasonable. And I would be tempted to call these people philosophically desperate.

I'd be tempted to call those people closet theists who are in denial, but maybe you're more polite than I am.

What I mean is that they have something in their system that is playing a god-like role, but they're "scientific", so it can't be God.

By the way, I would say the same about the "universe is a simulation" people.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#112

Post by Retric »

0majors wrote: post #83
Retric wrote: post #72

Earlier quoted context omitted.

All analogies are flawed because the underlying reality is different. They can still be useful if they can communicate some more abstract idea. An analogy I like for entanglement is to picture two atoms that will both decay at the same time. You could place them on other sides of the planet and until one is observed to decay nobody learns anything because the timing is unpredictable. After the observation people agre…

The problem with that analogy is it gives an illusion of understanding while being completely misleading about what Bell’s inequality actually tells us about nature. The whole point of Bell’s inequality is that quantum entanglement is fundamentally different than classical correlation between two objects which have some opposite properties the observer simply does not know about before observing one of them. It’s not…

No so fast, Bell’s inequality only invalidates local hidden variables. It’s your interpretation that’s suggesting some local variable like a ticking clock was determining when those atoms would decay, but that’s not part of the analogy.

The many worlds interpretation is analogous to global hidden variables, and while out of favor, perfectly consistent with modern physics. That said, the core issue is IMO only a one dimensional property was correlated which hides a lot of the oddities involved.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#113

Post by joe_the_user »

ericb wrote: post #3

If we were in a simulation, would the speed of light be the processing speed of the universe as each area re-renders, and spooky action at a distance be two variables pointed to the same memory location, populated with a lazy-loaded value, with copy-on-write semantics? edit: seems like it is lazy loaded, so revised my summary.

There are no propositions that "we are in simulation" would imply (unless someone fundamentally lacks imagination).

Being "in a simulation" doesn't imply that we're in simulation created by later humans, it doesn't give any indication how fine-grain the approximations are, etc. etc.

"We're in a simulation" fundamentally discard Occam's Razor in the fashion of the belief in God as controlling everything. And thus this belief has the same weight as belief in the Flying Spaghetti Monster [1].

[1] https://en.wikipedia.org/wiki/Flying_Spaghetti_Monster

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#114

Post by joe_the_user »

drcode wrote: post #34
nsxwolf wrote: post #27

I'll never understand entanglement. Every explanation makes me wonder why it can't be used to instantaneously send a message. I never fully understand the explanations why it can't be used to do so. I don't understand how you can be sure about the state of the other particle, what if someone already measured it and then did something to it?

Imagine you have a pouch with a red and a blue marble in it, then take out a marble without looking at it and hand the pouch to a friend. Later, if you look at your marble, you instantly have information about the other marble at a speed greater than the speed of light... but you couldn't use that fact to send a message. The only difference in quantum physics is that there are actually two parallel universes: One in…

Your discussion is inherently within the classical realm and so it doesn't explain the uniqueness of quantum phenomena. You easily have "classical many worlds" where unknown information makes a model "split" and gaining the information decides which split you get. That's still not quantum in particular.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#115

Post by fnord77 »

danbruc wrote: post #48
drcode wrote: post #34

Earlier quoted context omitted.

Imagine you have a pouch with a red and a blue marble in it, then take out a marble without looking at it and hand the pouch to a friend. Later, if you look at your marble, you instantly have information about the other marble at a speed greater than the speed of light... but you couldn't use that fact to send a message. The only difference in quantum physics is that there are actually two parallel universes: One in…

The only difference in quantum physics is that there are actually two parallel universes: One in which you took out the red marble & one in which you took the blue one. You don't know what universe you're in until you look at the marble, but still it doesn't help you to transmit a message to your friend. I don't think it is helpful to talk about multiple universes, that makes a strong implication towards a many world…

in this example, what evidence is there that it works differently than in the classical case?

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#116

Post by joe_the_user »

danbruc wrote: post #48
drcode wrote: post #34

Earlier quoted context omitted.

Imagine you have a pouch with a red and a blue marble in it, then take out a marble without looking at it and hand the pouch to a friend. Later, if you look at your marble, you instantly have information about the other marble at a speed greater than the speed of light... but you couldn't use that fact to send a message. The only difference in quantum physics is that there are actually two parallel universes: One in…

The only difference in quantum physics is that there are actually two parallel universes: One in which you took out the red marble & one in which you took the blue one. You don't know what universe you're in until you look at the marble, but still it doesn't help you to transmit a message to your friend. I don't think it is helpful to talk about multiple universes, that makes a strong implication towards a many world…

I don't think it is helpful to talk about multiple universes, that makes a strong implication towards a many world interpretation.

You're correct but the point is "many worlds" or Copenhagen interpretation having no implications, they each describe the same mathematical/experimental results. They're just "ways to think about the results". They matter as much as whether you label the axes of a graph x and y or A and B. So any theory that "requires" many worlds is inherently not looking using the standard interpretation of many worlds and quantum mechanics.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#118

Post by IncRnd »

joe_the_user wrote: post #113
ericb wrote: post #3

If we were in a simulation, would the speed of light be the processing speed of the universe as each area re-renders, and spooky action at a distance be two variables pointed to the same memory location, populated with a lazy-loaded value, with copy-on-write semantics? edit: seems like it is lazy loaded, so revised my summary.

There are no propositions that "we are in simulation" would imply (unless someone fundamentally lacks imagination). Being "in a simulation" doesn't imply that we're in simulation created by later humans, it doesn't give any indication how fine-grain the approximations are, etc. etc. "We're in a simulation" fundamentally discard Occam's Razor in the fashion of the belief in God as controlling everything. And thus this…

> "We're in a simulation" fundamentally discard Occam's Razor in the fashion of the belief in God as controlling everything. And thus this belief has the same weight as belief in the Flying Spaghetti Monster [1].

You are using Occam's Razor incorrectly. A preference for parismony in problem solving is not identical with parsimony being the only state of the world.

As a side note, which directly applies to your comment, Occam's Razor was invented by Friar William of Ockham as a defense of divine miracles.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#119

Post by naasking »

themgt wrote: post #16
nobodyandproud wrote: post #11

Earlier quoted context omitted.

Those objections to super determinism seem weak, or more along the lines of “I don’t like the implications, so I won’t consider it.” Genuine question: Would quantum computers work in any deterministic framework?

I've quoted it before but I will again just because I hate superdeterminism so much: First, the logical flow: Bell’s theorem proves that no local, realistic theory can reproduce the predictions of quantum mechanics. It does so by considering a very specific situation of entangled particles being measured by spin detectors set at different angles. Critically, the angles of these spin detectors are assumed to be set in…

> And that it’s possible that these things have conspired (unknowingly) to make sure that my detector settings and a particle’s spin measurement is correlated in a particular way in my lab in a law-like way.

Yes exactly, which is to say that your instrument calibration dicated by that elaborate randomization process, just ensures that the particle will arrive in a specific configuration, which is a purely local, realistic phenomenon.

Sabine and Palmer recently explained how superdeterminism can be understood easily as future input dependence:

https://www.frontiersin.org/articles/10.3389/fphy.2020.00139...

Edit: despite superdeterminism annoying you so much, I bet you're perfectly fine with general relativity in which time is just another space-like coordinate, and the correlation you describe is a perfectly well-defined path along a closed timelike curve. An interesting inconsistency if true.

Re: How Bell’s Theorem proved ‘spooky action at a distance’ is real

#120

Post by evanb »

Kranar wrote: post #46
tylerhou wrote: post #20

Earlier quoted context omitted.

A classical analogy for entanglement: suppose I have two balls in a bag. They are identical in every way, except one is red and the other is blue. I randomly grab one in each hand and show my hands closed. Now the states of the ball are entangled: as soon as you see the color of one ball, that "determines" the color of the other. (Not claiming that this is a perfect analogy, but I don't see where it diverges from how…

>They are identical in every way, except one is red and the other is blue. I randomly grab one in each hand and show my hands closed. Now the states of the ball are entangled: as soon as you see the color of one ball, that "determines" the color of the other. This gets used to explain entanglement but it really has absolutely nothing to do with it. This is nothing that the ancient Greeks wouldn't have known. Not to p…

Just to be absolutely pedantic,

"one of the balls is red and the other is blue"

IS a statement you can make. However, it's surprisingly not equivalent to asserting

    (xor (and (red?  'left) (blue? 'right))
         (and (blue? 'left) (red?  'right)))
That is, "one is red and one is blue" does not mean that it's the case that either has a definite color.

In terms of oft-used Bell pair states to demonstrate what I'm talking about, you can definitely say that total S^2=0.

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