Irreversible processes without energy dissipation in an isolated Lipkin-Meshkov-Glick model

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Date: 
2014-04-24 - 2015-07-02
Author(s): 

R. Puebla, A. Relaño

Reference: 

Phys. Rev. E 92, 012101

For a certain class of isolated quantum systems, we report the existence of irreversible processes in which the energy is not dissipated. After a closed cycle in which the initial energy distribution is fully recovered, the expectation value of a symmetry-breaking observable changes from a value differing from zero in the initial state to zero in the final state. This entails the unavoidable loss of a certain amount of information and constitutes a source of irreversibility. We show that the von Neumann entropy of time-averaged equilibrium states increases in the same magnitude as a consequence of the process. We support this result by means of numerical calculations in an experimentally feasible system, the Lipkin-Meshkov-Glick model.