Matter and antimatter: the two arrows of time

Abstract

Antiparticles may be interpreted as ordinary particles travelling backwards in time and the two descriptions are considered equivalent, at least in special relativity and relativistic quantum mechanics. It is suggested that, vice versa, the discovery of antimatter should be the confirmation that our world is "endowed" with two opposite time-arrows and such a description could be more useful and convenient from the point of view of the understanding of the world itself, at least for a simple reason: whenever phenomena are observed from a "reference frame" from which the world appears more symmetric, it is easier to understand the physical laws which regulate it. If, in the future, it is possible to discover how a macroscopic system of antimatter behaves, it will be also possible to confirm (or not) the "reality" of the two arrows of time.