| Abstract: | We investigate the dynamics of open quantum systems that violate detailed balance in equilibrium and examine how this deviation influences the system's relaxation toward thermal equilibrium. While detailed balance is often assumed in Markovian dynamics, it is not a requirement for the existence of a stationary state. By focusing on systems that break microreversibility and studying their thermalization beyond the weak coupling limit, we explore dynamics that extend beyond detailed balance. Specifically, we analyze a three-level system toy model in the low-density limit, where detailed balance may not strictly apply. Our findings reveal two primary types of relaxation dynamics, as well as a third transitional type, demonstrated through exceptional points. At high temperatures, we observe that the relaxation is accompanied by oscillations in the energy level populations, driven by the environment, and characterized by an energy scale related to the violation of detailed balance. These oscillations occur even in the absence of quantum coherences. |
