Tavis-Cummings模型中的几何量子失协特性  

Geometric quantum discord in Tavis-Cummings model

作　　者：程景 单传家 刘继兵 黄燕霞 刘堂昆 Cheng Jing;Shan Chuan-Jia;Liu Ji-Bing;Huang Yan-Xia;Liu Tang-Kun(College of Physics and Electronic Science, Hubei Normal University, Huangshi 435002, Chin)

机构地区：[1]湖北师范大学物理与电子科学学院,黄石435002

出　　处：《物理学报》2018年第11期51-56,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11404108);湖北省自然科学基金(批准号:2016CFB639)资助的课题~~

摘　　要：采用几何量子失协的计算方法,通过改变两原子初始状态、腔内光子数和偶极-偶极相互作用强度,研究了Tavis-Cummings模型中的几何量子失协特性.结果表明:几何量子失协都是随时间周期性振荡的,选取适当的初态可以使两原子一直保持失协状态,增加腔内光子数和偶极相互作用对几何量子失协有积极的影响.Quantum entanglement plays a key role in quantum information and quantum computation and thus attracts much attention in many branches of physics both in theory and in experiment. But recent studies revealed that some separable states （non-entangled state） may speed up certain tasks over their classical counterparts and may also possess certain kinds of quantum correlations. For example, geometric quantum discord, which is a more general quantum correlation measure than entanglement, can be nonzero for some separable states. From a practical point of view, it is proposed that the geometric quantum discord be responsible for the power of many quantum information processing tasks. In order to capture such correlations, Ollivier and Zurek introduced quantum discord, which measures the discrepancy between two natural yet different quantum analogues of two classically equivalent expressions of mutual information. However, the calculation of quantum discord is based on numerical maximization procedure, and there are few analytical expressions even for a two-qubit state. In order to obtain the analytical results of quantum discord, a geometric measure of quantum discord which measures the quantum correlations through the minimum Hilbert-Schmidt distance between the given state and zero discord state is introduced. Geometric quantum discord is defined as an effective measure of quantum correlation, and the geometric quantum discord through the minimal distance between the quantum state and the set of zero-discord states in a bipartite quantum system can be worked out. In this paper, by using the geometric quantum discord measurement method, the geometric quantum discord in Tavis-Cummings model is investigated, and the influences of the initial state purity, entanglement degree, dipole-dipole coupling intensity between two atoms, and field in the Fock state on the evolution characteristic of geometric quantum discord are analyzed. The results show that the geometric quantum discord appears periodically. It initially d

关 键 词：量子纠缠 几何量子失协 偶极-偶极相互作用 

分 类 号：O413[理学—理论物理]