Decoherence Rate in Random Lindblad Dynamics

Open quantum systems undergo decoherence, which is responsible for thetransition from quantum to classical behavior. The time scale in whichdecoherence takes place can be analyzed using upper limits to its rate. Weexamine the dynamics of open chaotic quantum systems governed by randomLindblad operators sourced from Gaussian and Ginibre ensembles withWigner-Dyson symmetry classes. In these systems, the ensemble-averaged puritydecays monotonically as a function of time. This decay is governed by thedecoherence rate, which is upper-bounded by the dimension of their Hilbertspace and is independent of the ensemble symmetry. These findings hold uponmixing different ensembles, indicating the universal character of thedecoherence rate limit. Moreover, our findings reveal that open chaotic quantumsystems governed by random Lindbladians tend to exhibit the most rapiddecoherence, regardless of the initial state. This phenomenon is associatedwith the concentration of the decoherence rate near its upper bound. Our workidentifies primary features of decoherence in dissipative quantum chaos, withapplications ranging from quantum foundations to high-energy physics andquantum technologies.