Thermodynamic arrow of time of quantum projective measurements
1 Department of Physics, Pusan National University - Busan 609-735, Korea
2 Department of Physics and BK21 Physics Research Division, Sungkyunkwan University Suwon 440-746, Korea
Received: 8 May 2013
Accepted: 16 July 2013
We investigate a thermodynamic arrow associated with quantum projective measurements in terms of the Jensen-Shannon divergence between the probability distribution of energy change caused by the measurements and its time-reversal counterpart. Two physical quantities appear to govern the asymptotic values of the time asymmetry. For an initial equilibrium ensemble prepared at a high temperature, the energy fluctuations determine the convergence of the time asymmetry approaching zero. At low temperatures, the finite survival probability of the ground state limits the time asymmetry to be less than ln 2. We illustrate our results for a concrete system and discuss the fixed point of the time asymmetry in the limit of infinitely repeated projections.
PACS: 05.70.Ln – Nonequilibrium and irreversible thermodynamics / 05.45.-a – Nonlinear dynamics and chaos / 03.65.Aa – Quantum systems with finite Hilbert space
© EPLA, 2013