Dynamic magnetization in non-Hermitian quantum spin systems

Article

关键词: EXCEPTIONAL-POINT;   

DOI  :  10.1103/PhysRevB.101.224301

来源: SCIE

【 摘 要 】

We report a global effect induced by the local complex field associated with the spin-exchange interaction. High-order exceptional point up to (N + 1)-level coalescence is created at the critical local complex field applied to the N-size quantum spin chain. The (N + 1)-order coalescent level is a saturated ferromagnetic ground state in the isotropic spin system. Remarkably, the final state always approaches the ground state for an arbitrary initial state with any number of spin flips, even if the initial state is orthogonal to the ground state. Furthermore, the switch of macroscopic magnetization is solely driven by the time and forms a hysteresis loop in the time domain. The retentivity and coercivity of the hysteresis loop mainly rely on the non-Hermiticity. Our findings highlight the cooperation of non-Hermiticity and the interaction in the quantum spin system, suggest a dynamical framework to realize magnetization, and thus pave the way for the non-Hermitian quantum spin system.

【 授权许可】

Free