Anomalous transport in U(1)-symmetric quantum circuits
摘要
In this work, we investigate discrete-time transport in a generic U(1)-symmetric disordered model tuned across an array of different dynamical regimes. We develop an aggregate quantity, a circular statistical moment, which is a simple function of the magnetization profile and which elegantly captures transport properties of the system. From this quantity, we extract transport exponents, revealing behaviors across the phase diagram consistent with localized, diffusive, and—most interestingly for a disordered system—superdiffusive regimes. Investigation of this superdiffusive regime reveals the existence of a prethermal “swappy” regime unique to discrete-time systems in which excitations propagate coherently; even in the presence of strong disorder.