Landauer's Principle in Repeated Interaction Systems

“We study Landauer’s Principle for Repeated Interaction Systems (RIS) consisting of a reference quantum system \(\mathcal{S}\) in contact with a structured environment \(\mathcal{E}\) made of a chain of independent quantum probes; \(\mathcal{S}\) interacts with each probe, for a fixed duration, in sequence. We first adapt Landauer’s lower bound, which relates the energy variation of the environment \(\mathcal{E}\) to a decrease of entropy of the system \(\mathcal{S}\) during the evolution, to the peculiar discrete time dynamics of RIS. Then we consider RIS with a structured environment \(\mathcal{E}\) displaying small variations of order \(T^{-1}\) between the successive probes encountered by \(\mathcal{S}\), after \(n\simeq T\) interactions, in keeping with adiabatic scaling. We establish a discrete time non-unitary adiabatic theorem to approximate the reduced dynamics of \(\mathcal{S}\) in this regime, in order to tackle the adiabatic limit of Landauer’s bound. Our analysis shows that, in general, Landauer’s bound for RIS is not saturated in the adiabatic regime, due to the entropy production inherent to the RIS dynamics. This is to be contrasted with the saturation of Landauer’s bound known to hold for continuous time evolution of open quantum system in the adiabatic regime."