Wang Xiaoqian, Ma Jian, Song Lijun, Zhang Xihe, Wang Xiaoguang
Department of Physics, Changchun University of Science and Technology, Changchun 130022, People's Republic of China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Nov;82(5 Pt 2):056205. doi: 10.1103/PhysRevE.82.056205. Epub 2010 Nov 12.
We study spin squeezing, negative correlations, and concurrence in the quantum kicked top model. We prove that the spin squeezing and negative correlations are equivalent for spin systems with only symmetric Dicke states populated. We numerically analyze spin squeezing parameters and concurrence in this model and find that the maximal spin squeezing direction, which refers to the minimal pairwise correlation direction, is strongly influenced by quantum chaos. Entanglement (spin squeezing) sudden death and sudden birth occur alternatively for the periodic and quasiperiodic cases, while only entanglement (spin squeezing) sudden death is found for the chaotic case.
我们研究了量子踢顶模型中的自旋压缩、负关联和并发度。我们证明，对于仅填充对称狄克态的自旋系统，自旋压缩和负关联是等效的。我们对该模型中的自旋压缩参数和并发度进行了数值分析，发现最大自旋压缩方向（即最小成对关联方向）受到量子混沌的强烈影响。对于周期和准周期情况，纠缠（自旋压缩）会交替出现突然死亡和突然产生，而对于混沌情况，仅发现纠缠（自旋压缩）突然死亡。
