system
Given the following post, respond as if you're commenting on Reddit:
human
If I accelerate and collect some particles produced by Unruh radiation in a jar. If I go to a friend who didn't accelerate and open the jar, what will we see?

Let me elaborate on this thought experiment.


So, I have a friend in an inertial frame of reference watching my every move with cameras and telescopes.

I accellerate till I notice Unruh radiation, let's say I accelerate hard enough to see electrons and positrons. I open up a jar and collect some electrons in it.  In the meantime, my friend has seen every action, but sees no Unruh radiation. He just sees me waving around with my jar in the vacuum.

But then I slow down and head back to him in his inertial frame of reference and show him the jar.
He knows the jar is empty, because he has seen me put nothing but a vacuum in them.  I know there are electrons in the jar, because I've put them in myself.


What would we see if we open the jar? Is it empty? or not?

If there are electrons, how did they emerge in my friends point of view?
If there are no electrons, where are they now?


And what about conservation of charge?
gpt
Very good question. The answer is that the presence/absence of particles is observer dependent, in particular it depends on your definition of vacuum (in case you have a strong background in physics this is related to the existence of a timelike Killing vector, that provides a preferred notion of time and hence a definition of positive frequency modes that we can associate with particles).

There is nevertheless no inconsistency or paradox, 2 observers in a curved spacetime won't agree on the particle content but will agree on the Energy-Momentum tensor and they know also how to calculate what each other sees.

In the particular example you provide, the jar will be empty for both observers once you go back to an inertial reference frame.