Mixed-state geometric phases of coherent and squeezed spin states
Abstract
Two mixed-state geometric phases, known as the Uhlmann phase and interferometric geometric phase (IGP), of spin coherent states (CSSs) and spin squeezed states (SSSs) are analyzed. Exact solutions and numerical results of selected examples are presented. For the CSS, the Uhlmann phase exhibits finite-temperature topological phase transitions characterized by abrupt jumps. The IGP for the same state similarly shows discontinuous jumps as the temperature varies. In the case of the one-axis SSS, both Uhlmann phase and IGP display discrete finite-temperature jumps. By contrast, the two-axis SSS shows no such transitions because the Uhlmann phase and IGP both vary smoothly with temperature. We also briefly discuss potential realizations and simulations related to these phenomena in spin systems.
Cite
@article{arxiv.2502.07268,
title = {Mixed-state geometric phases of coherent and squeezed spin states},
author = {Xin Wang and Jia-Chen Tang and Xu-Yang Hou and Hao Guo and Chih-Chun Chien},
journal= {arXiv preprint arXiv:2502.07268},
year = {2025}
}
Comments
13 pages, 6 figures, Fig. 5 updated