Quan, HT , Univ Hong Kong, Dept Phys, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China
部门归属:
Univ Hong Kong, Dept Phys, Hong Kong, Hong Kong, Peoples R China; Univ Hong Kong, Ctr Theoret & Computat Phys, Hong Kong, Hong Kong, Peoples R China; Chinese Acad Sci, Inst Theoret Phys, Beijing 100080, Peoples R China
英文摘要:
We explore a dynamic signature of quantum phase transition (QPT) in an isotropic Lipkin-Meshkov-Glick (LMG) model by studying the time evolution of a central qubit coupled to it. We evaluate exactly the time-dependent purity, which can be used to measure quantum coherence, of the central qubit. It is found that distinctly different behaviors of the purity as a function of the parameter reveal clearly the QPT point in the system. It is also clarified that the present model is equivalent to an anti-Jaynes-Cummings model under certain conditions.
Quan, H. T.,Wang, Z. D.,Sun, C. P.. Quantum critical dynamics of a qubit coupled to an isotropic Lipkin-Meshkov-Glick bath[J]. PHYSICAL REVIEW A,2007,76(1):-.
