Protecting quantum coherences from static noise and disorder

Quantum coherences are paramount resources for applications, such as quantum-enhanced light-harvesting or quantum computing, which are fragile against environmental noise. We here derive generalized quantum master equations using perturbation theory in order to describe the effective time evolution of finite-size quantum systems subject to static noise on all time scales. We then analyze the time evolution of the coherences under energy broadening noise in a variety of systems characterized by both short- and long-range interactions and by strongly correlated and fully uncorrelated noise —a single qubit, a lattice model with on-site disorder and a potential ladder, and a Bose-Hubbard dimer with random interaction strength—and show that couplings can partially protect the system from the ensemble-averaging induced loss of coherence. Our work suggests that suitably tuned couplings could be employed to counteract part of the dephasing detrimental to quantum applications. Conversely, tailored noise distributions can be utilized to reach target nonequilibrium quantum states