Timeline for Quantum entanglement, how do we know there was no spin?
Current License: CC BY-SA 4.0
8 events
when toggle format | what | by | license | comment | |
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Jun 19, 2018 at 14:44 | comment | added | alanf | @MoziburUllah You seem to have some disagreement with me. If you would like to discuss that disagreement my email is [email protected]. | |
Jun 19, 2018 at 13:25 | comment | added | Mozibur Ullah | Give it up Alan ... you might be able to fool other people with merely repeating half-digested jargon ad nauseam - but I'm afraid it doesn't fool me. | |
Jun 19, 2018 at 13:13 | comment | added | alanf | The electrons are entangled with respect to their spin. Each individual electron has a state that does not correspond to it having a particular spin: there is no direction in which its reduced density matrix will be |up><up| or |down><down|. | |
Jun 19, 2018 at 11:48 | comment | added | Mozibur Ullah | ... but a composite particle of two quarks - a meson; and as a composite particle it has total spin zero; this means when it decays into photons they will have opposite and equal spins. | |
Jun 19, 2018 at 11:47 | comment | added | Mozibur Ullah | but you begin your experiment with "suppose you have two electrons in a state of entangled spin"; so how can "they have no spin before" when you begin with them having spin? In fact, when a particle has spin it always has spin; it cannot not have spin; the only way this is possible is if you begin with a particle with no spin at all; that's why the comment above was interesting, because in their experiment they began with a pion which is not an elementary particle... | |
Jun 19, 2018 at 11:30 | comment | added | alanf | One way we know they had no spin before the measurement is that this is ruled out by experiment, as explained in my answer. | |
Jun 19, 2018 at 8:16 | comment | added | Mozibur Ullah | This isn't actually answering the question the OP is asking. An answer that does is actually posted under the comments to the question. It's short and it's relevant. | |
Jun 19, 2018 at 7:26 | history | answered | alanf | CC BY-SA 4.0 |