Decoherence, entanglement, and chaos in the Dicke model (6 pages)
Decoherence, entanglement, and chaos in the Dicke model (6 pages)
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DOI：
10.1103/physreva.69.042110
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发表时间：
2004-04
影响因子：
2.9
通讯作者：
Xi-Wen Hou
中科院分区：
文献类型：
--
作者：
Xi-Wen Hou
利用约化密度线性熵研究了非行波近似下迪凯模型中量子纠缠的动力学性质。数值计算了退相干过程的早期演化特征时间，发现退相干过程的早期演化特征时间随耦合参数的增大而减小。用平均纠缠度来描述量子相变和相应的经典混沌对纠缠行为的影响。对于一个给定的能量，初始条件被认为是最小的不确定性波包集中在规则和混沌区域的经典相空间。结果表明，在量子相变时，纠缠度有明显的变化，在弱耦合情况下，规则初始条件下的纠缠度小于混沌初始条件下的纠缠度，而在强耦合和混沌初始条件下，纠缠度有小幅波动.
The dynamical properties of quantum entanglement in the Dicke model without rotating-wave approximation are investigated in terms of the reduced-density linear entropy. The characteristic time of decoherence process in the early-time evolution is numerically obtained and it is shown that the characteristic time decreases as the coupling parameter increases. The mean entanglement, which is defined to be averaged over time, is employed to describe the influences of both quantum phase transition and corresponding classical chaos on the behavior of entanglement. For a given energy, initial conditions are taken to be minimum uncertainty wave packets centered at regular and chaotic regions of the classical phase space. It is shown that the entanglement has a distinct change at the quantum phase transition, and that the entanglement for regular initial conditions is smaller than that for chaotic ones in the case of weak coupling, while it fluctuates with small amplitude in strong coupling and for chaotic initial conditions.