Reversing time in quantum mechanics

CRISTIAN LÓPEZ

Leuven

Workshop; International Workshop Leuven-Buenos Aires; 2016

UK Leuven

The purpose of this presentation is to consider the problem of the arrow of time in quantum mechanics (QM). We will begin by recalling the different results obtained from applying the Wigner operator T* and the Racah operator T to the Schrödinger equation: QM is both T*-invariant theory and T-non-invariant. To tackle this situation, we will consider two alternatives: (i) to accept that QM is not time-reversal invariant, in contradiction to the commonly accepted assumption; (ii) to agree with the common opinion that QM is time-reversal invariant, but in contradiction to idea that the time-reversal operator must be defined independently of the theory. We will argue that the way out of this dilemma is to break the link between arrow of time and time-reversal invariance, and to appeal to another feature to distinguish between the two directions of time in all physical theories.