Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top
up vote 6 down vote accepted

The arrow is related to the flow of charge, not the direction of motion. So for antimatter they go the opposite way.

Or as some are fond of saying, the positron is like an electron moving backwards in time.

share|cite|improve this answer
Thanks! But moving backwards in time? This is a joke right? – kame Feb 21 '11 at 15:06
Not a joke at all. This isn't a joke either: – Keenan Pepper Feb 21 '11 at 17:00
@Keenan: ''moving backward in time'' is a relic from the times of the dirac sea. But in quantum field theory, all particles move forward in time (i.e., the momentum vector has a positive 0-component). – Arnold Neumaier Mar 25 '12 at 19:43

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.