AIP conference proceedings

Janus sequences of quantum measurements and the arrow of time

Andrew N. Jordan, Areeya Chantasri, Kater W. Murch, Justin Dressel, Alexander N. Korotkov

Published Jan 1, 2017• 0 citations

Abstract

We examine the time reversal symmetry of quantum measurement sequences by introducing a forward and backward Janus sequence of measurements. If the forward sequence of measurements creates a sequence of quantum states in time, starting from an initial state and ending in a final state, then the backward sequence begins with the time-reversed final state, exactly retraces the intermediate states, and ends with the time-reversed initial state. We prove that such a sequence can always be constructed, showing that unless the measurements are ideal projections, it is impossible to tell if a given sequence of measurements is progressing forward or backward in time. A statistical arrow of time emerges only because typically the forward sequence is more probable than the backward sequence.

DOI: 10.1063/1.4982767

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