Dynamics of 2×2 matrix non-Hermitian quantum systems on Bloch sphere  

作　　者：Libin Fu 

机构地区：[1]Graduate School of China Academy of Engineering Physics,Beijing 100193,China

出　　处：《Communications in Theoretical Physics》2024年第4期66-71,共6页理论物理通讯（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.12088101,and U2330401).

摘　　要：By casting evolution to the Bloch sphere, the dynamics of 2 × 2 matrix non-Hermitian systems are investigated in detail. This investigation reveals that there are four kinds of dynamical modes for such systems. The different modes are classified by different kinds of fixed points, namely,the elliptic point, spiral point, critical node, and degenerate point. The Hermitian systems and the unbroken PT non-Hermitian cases belong to the category with elliptic points. The degenerate point just corresponds to the systems with exceptional point(EP). The topological properties of the fixed point are also discussed. It is interesting that the topological charge for the degenerate point is two, while the others are one.

关 键 词：non-Hermitian quantum system two-level system dynamics on the Bloch sphere PT-SYMMETRY fixed points 

分 类 号：O511.3[一般工业技术—材料科学与工程]