Counteracting quantum decoherence with optimized disorder in discrete-time quantum walks

Decoherence and disorder are two major difficulties limiting the performance of quantum systems in practical settings. Yet they can potentially counteract each other to partially restore the systems' quantum signatures. We adopt the particle swarm optimization method to find the optimal disorder for mitigating the effects of decoherence in one- and two-dimensional quantum random walks, achieving substantial increase in the mean walking distance for a wide range of decoherence strength. This result suggests a viable approach to constructing practical quantum systems robust against decoherence and disorder.