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We know that there are parameters that are even under time-reversal T such as x, E, electric dipole moment, while others are odd, such as momentum p, t and B. Is there an intuitive way to figure out which one is even and which one is odd?

Thi Hoàng
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1 Answers1

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Just imagine “running the movie backward”.

The velocity and thus the momentum of moving particles obviously reverse. If the particles have charge, the current reverses so the magnetic field reverses.

The electric field and electric dipole moment are unrelated to motion so they don’t reverse.

G. Smith
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