Yupeng Wang: Superdiffusive transport in quasi-particle dephasing/disorder model

Most open quantum system models described by Lindblad master equation in previous literature exhibit (sub)diffusive transport. In this study, we explore the transport dynamics of the Lindblad master equation with free fermion Hamiltonian and quasi-particle projector Lindblad operator. We reveal that when the momentum distribution of quasi-particles has nodal points, superdiffusive transport could emerge. By studying the dynamics of the Wigner function, we rigorously elucidate how the dynamics of these enduring modes give rise to Levy walk processes, a renowned mechanism underlying superdiffusion phenomena.

This "nodal point" picture is simple and general. A similar story happens in disorder system. Unlike the 1D Anderson model, where all eigenstates are localized, we can substitute onsite disorders with quasi-particle disorders. When the momentum distribution of quasi-particle impurities exhibits nodal points, the system can sustain delocalized states, leading to the emergence of superdiffusive transport.