1. Thermal Entanglement of the Two-Qubit Heisenberg Spin Chain Coupled to a Single-Mode Cavity Field
- Author
-
Guo-Hong Yang, Pei-Hua Zhang, and Jun Jing
- Subjects
Physics ,Coupling constant ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Field (physics) ,General Mathematics ,Single-mode optical fiber ,Quantum Physics ,Critical value ,Resonance (particle physics) ,Coupling (physics) ,Qubit ,Quantum mechanics ,Spin (physics) - Abstract
Thermal entanglement of a two-qubit Heisenberg spin chain coupled to a single-mode cavity field is investigated. It is found that (1) thermal entanglement without the rotating-wave approximation (RWA) is explicitly smaller than that obtained with the RWA, which means that the counter-rotating terms have a large impact on thermal entanglement, therefore they cannot be neglected; (2) the case (ω≪Ω) is more beneficial for enhancing thermal entanglement than the resonance case (ω=Ω), the near-resonant case (ω≈Ω) and the case (ω≫Ω); (3) for thermal entanglement, there is a competition process between the exchange coupling J (the direct-coupling between the two two-level atoms) and the coupling constant g (which deduces the indirect effect between the two two-level atoms); the critical value of g increases with the spin coupling strength J.
- Published
- 2010
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