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4:85 While she is explaining the experiment, she says that “Victor sends a particle to Alice and Bob simultaneously.” But the word particle in physics and espe
by nyc111 4y ago
4:85 While she is explaining the experiment, she says that “Victor sends a particle to Alice and Bob simultaneously.”
But the word particle in physics and especially in Quantum Mechanics is undefined. High energy physicists call a statistical “bump” in data a particle. A particle can be a wave. It can be a sphere with a finite radius. Or it can be a mathematical point. All these things and many more are called "particle". So we have no idea what Victor sends to Alice and Bob unless she takes the time to define it, but she doesn’t.
- stjohnswarts 4y agoBut this is a quick explanation for laypersons and not a physics 681 post graduate class?
- nyc111 4y agoYou are right, I understand. But professional physicists too refuse to define the meaning of the word particle. For instance I asked physicist Joan Baez if he had an article where he clearly defines particle and he said "No." https://twitter.com/cavendish_exp/status/1580176599391285248?s=46&t=osDxmk79MD6MrluRdmdbeg https://twitter.com/cavendish_exp/status/1580176599391285248...
- gus_massa 4y agoThere are some weird things that a "particle" can do. I'm counting like 3 ways particles can be weird, very weird, extremely weird. Anyway, for these experiments, a particle is just a photon (or an electron). It can be approximated quite well using a small ball that is like a small rock. And even with the small ball approximation, you can reproduce the Bell's inequality experiment. It does not depend in the weirdest parts.
- nyc111 4y agoPhotons, by definition, exhibit both properties of waves and particles. But here too a clear definition of particle is lacking. Physicists say photons are quanta, and use quanta and particles as synonyms. Photons have zero mass so they don’t have a finite radius as miniture billard balls. So, we have no idea what Victor sends. By convention he sends “particles” and we are forbidden to ask how this word particle is defined. A good example showing that physics is done by authority.