Entanglement of Quantum Fluctuations in the Inflationary Universe
Entanglement of Quantum Fluctuations in the Inflationary Universe
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暴胀宇宙中量子涨落的纠缠
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Y. Nambu
中科院分区：
文献类型：
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作者：
Y. Nambu
我们研究了膨胀宇宙中标量场的量子纠缠。利用标量场的晶格模型引入二部系统，应用基于部分转置运算的可分性准则，数值计算了不同空间区域之间的二部纠缠。我们发现，当空间区域的大小超过哈勃视界时，初始纠缠态变为可分离或解纠缠态。这是量子涨落具有经典性的必要条件。进一步研究了经典分布函数出现的条件，发现该条件由标量场协方差矩阵辛特征值的不等式给出。
We investigate quantum entanglement of a scalar field in the inflationary universe. By introducing a bipartite system using a lattice model of scalar field, we apply the separability criterion based on the partial transpose operation and numerically calculate the bipartite entanglement between separate spatial regions. We find that the initial entangled state becomes separable or disentangled when the size of the spatial regions exceed the Hubble horizon. This is a necessary condition for the appearance of classicality of the quantum fluctuation. We further investigate the condition for the appearance of the classical distribution function and find that the condition is given by the inequality for the symplectic eigenvalue of the covariance matrix of the scalar field.