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Why quantum entanglement doesn't allow faster-than-light communication (2016)

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31–40 of 166 posts

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#31
post #5

Earlier quoted context omitted.

That precisely is so much of the appeal of The Expanse ! For getting around our solar system, take plausible, foreseeable tech and add just a bit of secret sauce (the Epstein drive). So,.. the evolutionary path of society as depicted in the series is plausible.

I wanted to like it so badly but the show just didn't hook me. Need to give it another chance sometime

The books are pretty good IMO.

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#32
post #7
post #3

The gap I still have in my understanding: One hypothesis is that there is no spooky action. One particle was 'always' going to resolve one way, likewise with the other. Like inspecting 'heads' on one side of a coin 'forces' 'tails' onto the other side. I accept that this coin-hypothesis has been disproved by people who actually know what they're talking about. But to me, this implies that you should build your spooky…

> I accept that this coin-hypothesis has been disproved by people who actually knows what they're talking about. The classical idea is more like as follows: you have a guy Charles who makes two letters each with a card in that has written on it either number 0 or 1, and gives one letter to Alice and another to Bob. Now, "entanglement" here is that if Charles writes 0 in Alice's letter he writes the number 1 in Bob's,…

I think it's more like 2 dice, which always land on opposite sides, so 1 and 6, 2 and 5 and so on.

And then a measurement isn't just to land a die, but also to choose which axis to measure - ie ask the dice are you a 1 or a 6. The other die magically spins around to the same axis and gives the corresponding result.

But I'm not sure this analogy is satisfactory and explains the 'spookiness' either.

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#33
Most people don't understand enough about the fundamental properties of modern Physics.

What we usually call the speed of light is in fact the maximum speed of information propagation.

It is not about light, and you should think about quantum entanglement as a hidden variable, there is no magic there.

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#34
post #29

Can we simply tell that the entanglement was collapsed on the other end? That would be sufficient to transmit information. If planet x is habitable when I get there, I measure/collapse this specific particle, whose counterpart is back on earth in a detector named "habitable". When the detector fires on earth because this particle was measured/collapsed on planet x, people on earth know planet x is habitable. There's…

A particle with entaglement is undistinguishable from a particle with no entanglement.

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#35
post #13

Earlier quoted context omitted.

Yeah, the whole "planet's climate is stable enough for a sapient species to evolve and become hyper-advanced yet so unstable they're going to be wiped out" is so, so stupid.

What’s stupid about it?

It's dumb on two levels. Firstly, for a planet to evolve sapient life it must be inhabitable for, at minimum, millions of years if not billions, therefore if this orbital instability was going to wipe out the trisolarans it would've done it already. Secondly, the trisolarans are hyper-advanced. They turn individual protons into sapient robots and play with antimatter, therefore they can make a damn air conditioner. Manufacturing habitats to isolate them from the effects of their orbit would be easier than almost every single other thing they do in the entire series, including transporting their whole species across interstellar distances. Some of the things they do would be harder than keeping their planet in a stable orbit by force.

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#36
post #29

Can we simply tell that the entanglement was collapsed on the other end? That would be sufficient to transmit information. If planet x is habitable when I get there, I measure/collapse this specific particle, whose counterpart is back on earth in a detector named "habitable". When the detector fires on earth because this particle was measured/collapsed on planet x, people on earth know planet x is habitable. There's…

Any time you feel tempted to treat collapse as an objective state of a single particle, remember that the collapse interpretation is mathematically indistinguishable from the multiverse interpretation. There's no test for whether collapse has happened other than measuring at both ends and comparing notes… and noticing that nature appears to be cheating somehow.

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#37
post #3

The gap I still have in my understanding: One hypothesis is that there is no spooky action. One particle was 'always' going to resolve one way, likewise with the other. Like inspecting 'heads' on one side of a coin 'forces' 'tails' onto the other side. I accept that this coin-hypothesis has been disproved by people who actually know what they're talking about. But to me, this implies that you should build your spooky…

At the quantum scale, you can't observe without interaction. And the interaction is always destructive (of information, not of the particle).

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#38
post #29

Can we simply tell that the entanglement was collapsed on the other end? That would be sufficient to transmit information. If planet x is habitable when I get there, I measure/collapse this specific particle, whose counterpart is back on earth in a detector named "habitable". When the detector fires on earth because this particle was measured/collapsed on planet x, people on earth know planet x is habitable. There's…

even if you could relay that one binary piece of information, that's one bit of an integer or string that could contain arbitrary information.

The only thing that is known is that the other entangled particle has opposite spin than what you register.

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#39
post #24
post #7

Earlier quoted context omitted.

> I accept that this coin-hypothesis has been disproved by people who actually knows what they're talking about. The classical idea is more like as follows: you have a guy Charles who makes two letters each with a card in that has written on it either number 0 or 1, and gives one letter to Alice and another to Bob. Now, "entanglement" here is that if Charles writes 0 in Alice's letter he writes the number 1 in Bob's,…

The key difference, unlike the usual sock example or your letter example, it is not about knowing. The superimposed quantum states have not been fixed. It is both colour or or letters or states at the same time all the time unlike it is measured. It is not the knowledge about a pre-existed, the individual state does not exist until measurement. That is the crazy part.

Yes they have, it's just that in quantum mechanics you can expand the state in different bases. The state still "exists" before it is measured, just in a non-separable superposition state (i.e. an entangled state)

Re: Why quantum entanglement doesn't allow faster-than-light communication (2016)

#40
post #3

The gap I still have in my understanding: One hypothesis is that there is no spooky action. One particle was 'always' going to resolve one way, likewise with the other. Like inspecting 'heads' on one side of a coin 'forces' 'tails' onto the other side. I accept that this coin-hypothesis has been disproved by people who actually know what they're talking about. But to me, this implies that you should build your spooky…

You cannot tell if a particle has been measured or not without...measuring it. The key to understanding this is that _any_ interaction with anything counts as a "measurement" from the particles perspective. I like to think that our simulation has a bandwidth compression algorithm that only decodes the state of a particle when it needs to calculate an interaction. Just like how your dungeon crawler doesn't spawn mobs…

I don't dispute this, but it's indistinguishable from the 'no spooky action' hypothesis.

I can invent a story that the coin in my pocket has two sides, each of which is in a superposition of heads and tails.

If you disprove that by repeatedly looking at both sides and noting that they always end up different, then I can invent the story that the observed side tells the unobserved side what to become.

If you disprove that by separating the sides by a great distance before observing them both, I can invent the story that they coordinate instantaneously, ignoring the speed of light.

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