CPT symmetry and antimatter gravity in general relativity
INAF, Osservatorio Astronomico di Torino - Via Osservatorio 20, I-10025 Pino Torinese (TO), Italy, EU
Accepted: 12 March 2011
The gravitational behavior of antimatter is still unknown. While we may be confident that antimatter is self-attractive, the interaction between matter and antimatter might be either attractive or repulsive. We investigate this issue on theoretical grounds. Starting from the CPT invariance of physical laws, we transform matter into antimatter in the equations of both electrodynamics and gravitation. In the former case, the result is the well-known change of sign of the electric charge. In the latter, we find that the gravitational interaction between matter and antimatter is a mutual repulsion, i.e. antigravity appears as a prediction of general relativity when CPT is applied. This result supports cosmological models attempting to explain the Universe accelerated expansion in terms of a matter-antimatter repulsive interaction.
PACS: 04.90.+e – Other topics in general relativity and gravitation (restricted to new topics in section 04) / 11.30.Er – Charge conjugation, parity, time reversal, and other discrete symmetries / 98.80.-k – Cosmology
© EPLA, 2011