Strong-coupling quantum thermodynamics far from equilibrium: Non-Markovian transient quantum heat and work

In this paper, we investigate the strong-coupling quantum thermodynamics of a hybrid quantum system far from equilibrium, based on the renormalization theory of quantum thermodynamics we developed recently [Phys. Rev. Research 4, 023141 (2022)]. The strong-coupling hybrid system consists of a superconducting microwave cavity and a spin ensemble of the NV centers in diamond under external driving. The non-Markovian dynamics of this strong-coupling hybrid system has been experimentally explored and theoretically investigated. We apply the renormalization theory of quantum thermodynamics to study the transient quantum heat and work in this strong-coupling hybrid system. We find that the dissipation and fluctuation dynamics of the system induce the transient quantum heat current which shows significant non-Markovian effects. On the other hand, the energy and driving field renormalization produces quantum work power. In particular, the driving-induced work power can be largely enhanced by non-Markovian dynamics through the cavity coupling strongly with the spin ensemble at the resonance. Our results show that non-Markovian dynamics makes faster energy conversion of the heat and work.