Geometric Phase of Two-Level Mixed State and Bloch Sphere Structure

摘要

Geometric phase of two-level mixed state is investigated by comparing our approach with kinematic one. The results show that in the kinematic one, the Berry phases emerge discontinuous points because of losing a physical contribution from one of two eigenstates of density matrix. In contrast, our approach is a smooth curve of initial angle, evolving time and decay rate because of the interference between the two eigenstates with the probability ensemble.