Protecting quantum coherences from static noise and disorder

TL;DR

This paper develops generalized quantum master equations to analyze how static noise affects quantum coherences in various systems, revealing that couplings can mitigate coherence loss and tailored noise can generate specific quantum states.

Contribution

It introduces a perturbation theory-based framework for ensemble-averaged quantum dynamics under static noise, highlighting protection mechanisms and state engineering strategies.

Findings

Couplings can partially protect quantum coherences from static noise.

Tuned interactions can counteract dephasing in quantum systems.

Tailored noise distributions enable reaching specific quantum states.

Abstract

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 ensemble-averaged time-evolution of finite-size quantum systems subject to static noise on all time scales. We then analyse the time-evolution of the coherences under energy broadening noise in a variety of systems characterized by both short and long-range interactions, by strongly correlated and fully uncorrelated noise -- a single qubit, a lattice model with on-site disorder and a potential ladder, and bosons in a double-well potential 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 non-equilibrium quantum states.