Anonymous at Mon, 29 Jul 2024 18:43:56 UTC No. 16302176

Am I the only person who actually questions this "evidence?"

Anonymous at Mon, 29 Jul 2024 18:47:52 UTC No. 16302183

>>16302176
yes

Anonymous at Mon, 29 Jul 2024 19:25:46 UTC No. 16302265

>>16301092
To create a pair of entangled photons, a laser beam is directed at a nonlinear crystal, such as beta barium borate (BBO), in a process known as spontaneous parametric down-conversion (SPDC). In this process, a high-energy photon from the laser interacts with the crystal and splits into two lower-energy photons, called the signal and idler photons. The crystal is oriented to ensure phase matching, which conserves energy and momentum, and specific configurations of the crystal produce entangled polarizations in the resulting photon pair.

Anonymous at Mon, 29 Jul 2024 20:19:02 UTC No. 16302354

>>16302265
Yes, that is precisely what I don't quite get.
By producing two photons at the same time, you are merely guaranteeing a certain phase relation. How does that, in any way, imply entanglement?

Anonymous at Mon, 29 Jul 2024 20:25:52 UTC No. 16302363

>>16301092
> when Bob measures one as (+), Alice will always measure the other as (-)?
It's not as simple as that. For example instead of measuring up/down you measure up/left or at some other angle? The simplistic classical result is not what is observed.

Anonymous at Mon, 29 Jul 2024 20:28:44 UTC No. 16302367

>>16302354
BELLS THEOREM
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L
L
S

Anonymous at Mon, 29 Jul 2024 20:42:07 UTC No. 16302390

>>16302354
>>16302354
They are entangled because to know information about the state of one tells you about the state of the other. A simplified example would be this: you know that coins have one heads side and one tails side. Now flip a coin. Say that you see that the heads side is facing up. Despite the fact that you aren't directly interacting with the tails side, you know that the other side has to be tails because the side you are looking at is heads. That's all entanglement really is, it's when two pieces of information are connected together (one might say that the pieces of information are tangled together like how the wires of headphones or whatever else always seem to get twisted around each other).

Anonymous at Mon, 29 Jul 2024 20:43:45 UTC No. 16302391

>>16302390
Entanglement is non-classical. Your example doesn't work

Anonymous at Mon, 29 Jul 2024 20:57:57 UTC No. 16302414

>>16302367
Everything I have read about this is incomprehensible. Can you summarize it, for the class?
*pulls out notepad*

Anonymous at Mon, 29 Jul 2024 21:17:10 UTC No. 16302442

>>16302414

Take 3 cards prepared in a special "quantum" way. You are allowed to choose 2 of these cards and reveal them. Each card has 1 of 2 possible values

You find when you reveal them that the cards always have opposite values. How can this be explained in a classical way? Two of the cards must have the same value, but they never do. This is the core of bell's theorem.

Anonymous at Mon, 29 Jul 2024 21:18:42 UTC No. 16302445

>>16302391
I said it was simplified retard. The point is that entanglement is when two particles have interacted in some way by which knowing information about one necessarily gives you information about the other.

Anonymous at Mon, 29 Jul 2024 21:19:41 UTC No. 16302449

>>16302445
It's simplified but it's also wrong.

Anonymous at Mon, 29 Jul 2024 21:46:30 UTC No. 16302477

>>16302442

Anonymous at Mon, 29 Jul 2024 21:46:48 UTC No. 16302478

>>16302442
>How can this be explained in a classical way?
By stable phase relations. All that tells you is that the two photons generated by BBO aren't of random phase, they're strictly inversions of each other.
The "cards" aren't truly picked at random. It's like saying the "deck" only had two cards to begin with, and after the first is proven to be state 1, the other, by process of elimination, must be state 2.

Anonymous at Mon, 29 Jul 2024 21:51:25 UTC No. 16302480

>>16302478
>The "cards" aren't truly picked at random

Superdeterminism? Interesting interpretation.

Anonymous at Mon, 29 Jul 2024 21:57:47 UTC No. 16302486

>>16302480
Why would you assume an optical phenomenon is devoid of strict phase relations? Especially one that splits a photon into two

Anonymous at Mon, 29 Jul 2024 21:59:39 UTC No. 16302487

>>16302486
I suggest you read some literature on Bell's Theorem.

Anonymous at Mon, 29 Jul 2024 22:11:50 UTC No. 16302499

>>16302487
I have, and I'm not seeing any conflicts with what I'm saying. Are you sure you know what you're talking about?

Anonymous at Tue, 30 Jul 2024 03:47:37 UTC No. 16302805

>>16301092
It's easier to understand entanglement in the context of electrons.

Consider the decay of a neutral pion. There is an uncommon decay route where a neutral pion will decay to an electron and a positron. Pions are spin zero particles with no angular momentum, so the total angular momentum of the decay products must also be zero. Electrons and positrons are spin 1/2 particles, and must either be spin up or spin down. For their angular momentum to sum to zero, one must be spin up and the other spin down.

Which particle will be spin up? Charge symmetry is conserved, so both results are equally likely. The electron and the positron form an entangled pair.

Anonymous at Tue, 30 Jul 2024 04:28:52 UTC No. 16302828

>>16301092
Maybe it will help to remember that if those two "entangled" photons ever meet back up, they'll be out of phase and maybe, just maybe, they'll convert over to a tiny bit of matter, or a scalar wave interference.

VX

Anonymous at Tue, 30 Jul 2024 14:08:31 UTC No. 16303271

>>16302805
>Charge symmetry is conserved, so both results are equally likely.
Okay.
>The electron and the positron form an entangled pair.
I'm still not seeing the jump in logic here. Is "entanglement" literally just charge balance?

>>16302828
But that's just two antiparticles annihilating. Where does the spooky action come in?

Anonymous at Tue, 30 Jul 2024 14:09:32 UTC No. 16303273

*spin balance, not charge balance