2024/08/19 by Jinling Lian, Ran Huang, Lian, Jinling +9
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Quantum Mechanics and Applications #Quantum Physics (quant-ph) #Quantum optics and atomic interactions
paper · pdf · doi:10.48550/arxiv.2408.10121
openalex publication_date 2024/08/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate the ground-state properties and quantum phase transitions of an ensemble consisting of N four-level atoms within an optical cavity coupled to the single cavity mode and external laser fields. The system is described by an extended imbalanced Dicke model, in which the co- and counterrotating coupling terms are allowed to have different coupling strengths. Some novel polarized phases characterized by the phase differences between the cavity field or the atomic spin excitation and the Raman laser are found analytically. Meanwhile, the full phase diagram and quantum phase transitions are also revealed. Finally, the breaking or restoration of the intrinsic symmetry in this system is addressed. It is found that besides the continuous U(1) and discrete ℤ2 symmetries, the system also exhibits two reflection symmetries σvs, a central symmetry C2 in the abstract position-momentum representation, and a discrete reflection parity-time (PT) symmetry, a parameter exchange symmetry Tex in the parameters space. These additional symmetries are governed by two Coxeter groups.