On 19 May 2020 at 13:33, Richard Aiken wrote:

> What happens when different observers look at each entangled
> particle? That is, one observer looking at the one Here and another
> observer looking at the one Over There?

That's exactly how they proved non-locality.

The entangled particles are created and sent in different directions.

At the "end" of each run there's a detector that measures a property
of the particle. Usually it's photons and they are measuring
polarization. Say "up-down" vs "right-left".

As part of proving the non-locality, the setup doesn't "decide" which
way the detectors are set until *after* the photons are emitted.

If both detectors are set the same, you get either a detection at
both (if they are aligned with the polarization) or a failure at
both.

If they are set differently, the one that's aligned properly gets a
detection and the other one doesn't.

If the hidden variables model was correct, you'd get a certain
statistical pattern in the measures. If the state isn't determined
until you measure it, you get a different set of statistics. You'll
have to google things for details.

anyway, the results of many, *many* tests by various labs all show
that the state isn't determined until it's measured.
So as one physicist said long ago in reply to Einstein's assertation
that "God does not play dice with th universe", "Not only does God
play dice, He sometimes throws them where they cannot be seen".

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com