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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

#191

Post by danbruc »

joe_the_user wrote: post #152
danbruc wrote: post #136

Earlier quoted context omitted.

Even if they have no observable differences, they still make different metaphysical claims. If I see Schrödinger's cat alive, many world claims that there actually also exists a dead cat while Copenhagen claims that there is only one alive cat. You may argue that the differences are irrelevant for all practical purposes but you don't get to claim that there are no differences between different interpretations.

You may argue that the differences are irrelevant for all practical purposes but you don't get to claim that there are no differences between different interpretations. It depends what one considers "significant differences". If I go from caring about the practical implications of an interpretation to some other implications, I could make all sorts of distinctions. Explanation X might be written in French and explana…

If you are only worried about analyzing a specific quantum system, then yes, for most part the interpretation does probably not matter. But I think in general the differences are very important, especially as we do not understand quantum mechanics and different interpretations will direct future research in different directions. If you believe in Copenhagen, you will try to figure out how to reconcile unitary evolution with wave function collapse. If you believe in Bohmian mechanics, you will think about the quantum equilibrium hypothesis. If you believe in many worlds, you might be thinking about energy conservation.

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

#192

Post by qwerty456127 »

uh_uh wrote: post #190
qwerty456127 wrote: post #179

How long is it going to take until we can have a near-zero-latency Internet connection on Mars (e.g. on a Mars rover) or Moon?

You can not use QM for faster-than-light communication: https://en.wikipedia.org/wiki/No-communication_theorem

U.S. Department of Energy unveils blueprint for the quantum internet: https://news.fnal.gov/2020/07/u-s-department-of-energy-unvei...

Fermilab and partners achieve sustained, high-fidelity quantum teleportation: https://news.fnal.gov/2020/12/fermilab-and-partners-achieve-...

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

#193

Post by nimih »

willyg123 wrote: post #4

What is the prevailing theory to explain quantum entanglement? Must there be another dimension we cannot access or measure that is not subject to the laws of relativity? (I understand the laws of relativity break down at the quantum level but please ELI5)

The prevailing theory that explains quantum entanglement is precisely the theory of quantum mechanics, OP. If you're genuinely curious, I strongly encourage you to obtain an undergraduate degree in physics, which will equip you with the mathematical and theoretical background to see how the one explains the other.

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

#194

Post by joe_the_user »

naasking wrote: post #126
UncleOxidant wrote: post #124

Earlier quoted context omitted.

It's kind of interesting how people who would never consider a creationist explanation seem quite willing to embrace the idea that we're in a simulation.

One is an assertion with no logic to justify it, the other is an assertion with a somewhat persuasive argument justifying it [1]. They are simply incomparable. [1] https://www.simulation-argument.com/simulation.html

I actually think the singularity is an interesting concept deserving of exploration. But "singularians" like Nick Bostrom (author of parent link) have some strange ideas.

A. The idea that intelligence beyond human beings would grant it's possessor power that are in ways absolute in very specific, rigid fashion. Human being can accomplish a lot of things. It's notable those things human beings do better than computers seem very tenuous. Humans seem to drive rather haphazardly yet humans drive much better than computers and driving overall seems a "bucket chemistry" sort of activity. Humans calculate much worse than computers and calculation is an exact, defined activity (arguable, the exact, defined activity). But for the singularians, transhuman devices will do the uncertain, tenuous activities that humans do but with "no mistakes". And for a lot human activities, "no mistakes" actually might not even mean anything. Despite humans driving better than computers, humans probably wouldn't even agree on what absolute good driving even means.

B. Simulation as exact map. Any human created simulation of some system is going to be an approximation of that system for the purpose of extracting particular phenomena. Some things are discarded, other focused on and simplified. A model of the solar has to consider conservation of energy or tiny deviations will produce instability over time since errors overall on unavoidable in current hardware. Even a simulation of a computer chip isn't useful unless one knows the chip's purpose is logical operations. But for Bostrom and partisans of

C. Incoherent ontology. If we could produce an exact model of a thing, which is the real subject and which is simulation? What if we could produce twenty "exact simulations", which is real? In a realm of unlimited hypotheticals and unlimited exact simulations, wouldn't a least a countable infinite simulations of "everything" exist. Which is real is quite a conundrum but this problem itself only exists in a world of multiplied objects which we actually have no reason to suppose exists.

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

#195

Post by ks1723 »

mr_gibbins wrote: post #185
Kranar wrote: post #46

Earlier quoted context omitted.

>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…

No, I'm sorry, I'm not going to pull out heaps of regurgitated quantum information to back this up but that's straight-up wrong. The red ball and the blue ball exist as physical objects, it is us, the observers, who are unaware of whether they are red or blue at either position. There's no superposition here. They are red, or blue, assigned randomly. Not both, not none. These are facts - properties - about the balls…

Sorry, this is just wrong. Bell‘s inequality and the very related Bell-Kochen-Specker theorem [1] state that local hidden variables (one ball is blue, one is red, but we just don’t know it) are not consistent with QM.

[1] https://en.m.wikipedia.org/wiki/Kochen–Specker_theorem

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

#196

Post by joe_the_user »

naasking wrote: post #158
feoren wrote: post #135

Earlier quoted context omitted.

Of the 3 assertions in the abstract, the obviously false one is #2: "Any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history". When you realize that running a simulation of the universe requires more processing power than is available in the universe, this is very obviously false. I respect people who believe in a bearded White omnipotent homophobic Go…

> Of the 3 assertions in the abstract, the obviously false one is #2: "Any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history". When you realize that running a simulation of the universe requires more processing power than is available in the universe, this is very obviously false. I think you've expressed a number of confusions. First, I think you co…

First, I think you contradicted yourself. The line you quote says that posthuman civilizations are unlikely to create simulations, but you say this is false because a universe simulation requires more power than available in the universe

No, they are saying the opposite. The argument that simulating the universe requires more atoms than the universe says that a later civilization would not simulate the entire universe. IE, #2 of the refutations really true.

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

#197

Post by normac2 »

0majors wrote: post #95
normac2 wrote: post #88

Earlier quoted context omitted.

You describe that as an analogy, but I always took that to be what it actually is (or at least one very simple example). Are you saying that that is how we interpret our experience intuitively, but we need a more radical account under the various mainstream interpretations of quantum physics (Many Worlds, Copenhagen, etc.)?

That’s right. Not only it’s an analogy, it is also a bad one and completely misleading, at least according to physics of the last 50 years. Note how the article frets about the loss of locality.

Hmn. Is that at least what we experience if we try it as an experiment (even if the underlying physics is quite different than what it seems)?

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

#198

Post by lisper »

gus_massa wrote: post #189
lisper wrote: post #143

Earlier quoted context omitted.

What can I say? You're wrong. The math shows that you're wrong (as does the elementary argument presented in the paper). Find a physicist and ask them if you don't believe me.

I have at least 8 Physicist that I email/zoom regularly (at least twice per month). I also have half a degree in Physics, with at least 2 courses of Quantum Mechanics (all the advanced courses also use QM, but there are 2 courses only about QM). [I also have a degree and a PhD in Math, but it's not too relevant here.] Anyway, I'll read the article thoughtfully and write a long comment tomorrow. Can you take a look to…

Sure.

Just to be clear, the part you are wrong about is this:

> If you only have a single member of the pair, then you will see the same interference pattern in a double slit experiment than with a not-entangled particle.

This bit:

> It doesn't matter if the other particle has collided with a brick, went thru a double slit experiment, went thru a bad double slit experiment, or is flying to Andromeda.

is correct.

Also, there is an interference pattern in the results of a double-slit run on entangled particles, but it is not "the same" as you get with non-entangled particles, and the procedure you have to go through to observe this interference pattern is radically different.

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

#199

Post by wizzwizz4 »

eggsby wrote: post #100
wizzwizz4 wrote: post #28

Earlier quoted context omitted.

There actually is empirical foundation for the communication of the effects![0] But the model is strictly simpler if you remove the astrology from it; astrology has no additional explanatory power, and its novel claims (claims not predicted by any other model) are wrong. > Such children are more likely to be picked for school teams. Once they are picked, players benefit from more practice, coaching and game time — ad…

Sorry if my language was unclear, I meant to highlight this line from the wiki article: "There is no proposed mechanism of action by which the positions and motions of stars and planets could affect people and events on Earth in the way astrologers say they do that does not contradict well-understood, basic aspects of biology and physics." Relevant here because it essentially says "there is no empirical basis for spo…

> 'the relative positions of celestial bodies influence events on the earth'.

Who's claiming that‽ The relative positions of celestial bodies have influenced all sorts of events. For instance, the horoscopes in the newspaper, or photographs of the night sky.

No, what's in doubt is astrology, which is a much more specific set of (wrong) claims.

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

#200

Post by tbabb »

danbruc wrote: post #187
tbabb wrote: post #153

Earlier quoted context omitted.

it actually introduces many worlds No, this is the misunderstanding that I'm talking about. The extra "worlds" follow directly and exclusively from the existence of the various basis states in a wave function, and the laws of entanglement. No other postulates are needed. Before the measurement/entanglement, the system and environment are independent, and can be written (|0> + |1>) ⊗ (|0> + |1>). After the entanglemen…

The extra "worlds" follow directly and exclusively from the existence of the various basis states in a wave function, and the laws of entanglement. No other postulates are needed. The many worlds are in the entangled state but then the collapse postulate reduces them to one world. If you remove the collapse postulate you put them back in. And sure, the collapse postulate is an awful solution breaking unitary evolutio…

The distinction between "adding" and "removing" a postulate is an important, non-arbitrary one.

The "worlds" are there in both theories; Copenhagen adds a new phenomenon (non-unitary evolution) which makes some of them disappear at unspecified times. The "worlds" are direct consequences of suppositions shared with Copenhagen.

Many worlds has N postulates, Copenhagen has no fewer than N+1. One theory is a strict subset of the other's premises. It is not at all accurate to say that many worlds is the one that "introduces" suppositions.

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