Non-Hermitian spin-orbit coupling and beyond

Spin-orbit coupling, as an effective tool for exploring topological insulators, has been extensively studied in well-isolated Hermitian systems and recently been brought to the open quantum system with gain and loss described by a non-Hermitian Hamiltonian [1]. Here, we demonstrate new tools for non-Hermitian spin-orbit coupled systems. First, we introduce Floquet engineering to the non-Hermitian topological lattice by applying a periodic driving signal to the spin-orbit coupling. This approach allows us to investigate the interplay between Floquet engineering and non-Hermitian physics, including the non-Hermitian skin effect [2]. We also explore higher-order exceptional points (EPs) in a dissipative three-level spin-orbit-coupled fermions system. The tunable dissipation in this system enables us to observe abrupt phase transitions and adjust the energy gap.