Bell's Inequality: The weirdest theorem in the world – Nobel Prize 2022 | Hacker News Reader

Bell's Inequality: The weirdest theorem in the world – Nobel Prize 2022

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6 pointsnyc1117 comments

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.

But this is a quick explanation for laypersons and not a physics 681 post graduate class?

You 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...

There 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.

Photons, 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.

"[Bell] showed that if you only assume two things those things being local realism locality meaning you can't travel faster than the speed of light and realism which means that things have definite values whether or not you measure them..."

I don't think it is justified to assume that "things have definite values" independent of measurement.

Measurement just means some interaction. I find it impossible to believe that there are objects, somewhere, that are not interacting with some other object. Or that objects manifest physical properties only at the instant that they interact.

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