Spin Squeezing for Two Atoms in an Optical Coherent-State Cavity
We in this paper investigate the spin squeezing in relation with the phase transition from the normal to superradiant phases for two atoms in an optical cavity. The squeezing vanishes in the normal phase and jumps sharply to the maximum bound above the critical point of phase transition. In the high atom-field coupling regime, the squeezing vanishes again when the atom-field coupling reaches a threshold value. The squeezing alternates between two spin components in the intermediate region of atom-field coupling. An interesting observation is that the two spin components are squeezed alternately with the variation of phase angle of the cavity field. The squeezing factor indeed can be used to probe the phase transition and coherent-field properties as well.
KeywordsSpin squeezing Optical cavity Phase transition
This work was supported by the Natural Science Foundation of China under Grants Nos. 11105087, 11275118, 11404198 and the natural science foundation of Shanxi Province under Grant No. 201701D221001. This work was also sponsored by the Fund for Shanxi “1331 Project” Key Subjects Construction.