Irreversibility at zero temperature from the perspective of the environemnt

We address the emergence of entropy production in the non-equilibrium process of an open quantum system from the viewpoint of the environment. By making use of a dilation-based approach akin to Stinespring theorem, we derive an expression for the entropy production that comprises two fundamental contributions. The first is linked to the rate of creation of correlations between system and environment whereas the second highlights the possibility for the environment to modify its state in light of its coupling to the system. Both terms are shown to be associated with irreversible currents within the system and the environment, which pinpoint the emergence of irreversibility in the Markovian limit. Finally, we discuss how such a change of perspective in the study of entropy production has fecund implications for the study of non-Markovian open-system dynamics.