Time-reversal symmetry and fluctuation relations in non-equilibrium quantum steady states (Q2854128)

The aim of this article is to present a simple derivation of fluctuation relations for non-equilibrium quantum steady states from time-reversal symmetry, and a condition of pure transmission which implies an extended version of these relations. The authors' setup consists in considering two quantum systems prepared at different temperatures and chemical potentials, which are put into contact at some initial time, so that energy and charge flow from one system to the other. Assuming that steady state is reached at large times, the authors show the following:NEWLINENEWLINEa) The existence of time-reversal symmetry ensures that fluctuation relations hold for the large deviation function of energy and charge transfers in non-equilibrium steady states.NEWLINENEWLINEb) A condition of pure transmission implies that the large deviation function is linked to the mean currents but at shifted temperatures and chemical potentials. This then implies that all cumulants can be obtained from the mean current alone, and also that all cumulants, including the current, can be obtained from the equilibrium cumulants. The condition of pure transmission demands that energy emanating from the far left (right) goes through the system towards the far right (left) without being reflected.