Engineering Dynamical Couplings for Quantum Thermodynamic Tasks

Describing the thermodynamic properties of quantum systems far from equilibrium is challenging, in particular when the system is strongly coupled to its environment, or when memory effects cannot be neglected. Here, we address such regimes when the system-bath couplings are periodically modulated in time. We show that the couplings modulation, usually associated with a purely dissipative effect, can be suitably engineered to perform thermodynamic tasks. In particular, asymmetric couplings to two heat baths can be used to extract heat from the cold reservoir and to realize an ideal heat rectifier, where the heat current can be blocked either in the forward or in the reverse configuration by simply tuning the frequency of the couplings modulation. Interestingly, both effects take place in the low-temperature, quantum non-Markovian regime. Our work paves the way for the use of optimal control techniques for heat engines and refrigerators working in regimes beyond standard approaches.