Speaker: 徐志浩，山西大学

Inviter: 夏旭

Title: Localization Transition and Many Body Localization in Non-Hermitian Systems

Language: Chinese

Time & Venue: 2024.09.03 10:00-11:00 S425

Abstract: This talk is divided into two parts. The first part explores exact mobility edges (MEs) and topological phase transitions in a two-dimensional (2D) quasicrystal. We introduce a solvable 2D quasicrystal model with parity-time (PT) symmetry that exhibits exact MEs. In the thermodynamic limit, the extended-localized transition, occurring at the PT symmetry breaking point, is topological, characterized by a hidden winding number. This model can be realized in a coupled waveguide platform, where localization features are detectable through excitation dynamics. The second part addresses many-body localization (MBL) in non-Hermitian systems. We study a one-dimensional interacting Stark model with nonreciprocal hoppings, exhibiting three phase transitions under periodic boundary conditions: real-complex eigenenergy transition, topological phase transition, and non-Hermitian Stark MBL transition. These transitions are analyzed using level statistics, demonstrating that non-Hermitian Stark MBL shares similarities with disorder-induced MBL. The dynamical evolution of entanglement entropy and density imbalance differentiates the real-complex and Stark MBL transitions. Under open boundary conditions, the real-complex transition is absent, while the Stark MBL transition remains unchanged.