标题： 标量场在压缩态中的纠缠熵 显示英文标题

标题： Entanglement Entropy of a Scalar Field in a Squeezed State

摘要： 我们研究了在3+1维中，自由标量场在压缩态下的球形区域内的纠缠熵。 我们证明了，即使对于小的压缩，也会出现一个体积项，其系数基本上与场质量无关。 这与Page的论点一致，即任意量子态中的纠缠熵与较小子系统的自由度数成正比。 因此，可以将压缩态视为任意量子态，这与产生由与分隔表面面积成比例的项主导的纠缠熵的基态或相干态形成对比。 显示英文摘要

摘要： We study the entanglement entropy within a spherical region for a free scalar field in a squeezed state in 3+1 dimensions. We show that, even for small squeezing, a volume term appears, whose coefficient is essentially independent of the field mass. This is in line with Page's argument that the entanglement entropy in an arbitrary quantum state is proportional to the number of degrees of freedom of the smaller subsystem. It follows that squeezed states can be considered as arbitrary quantum states, in contrast to the ground or coherent states that give rise to entanglement entropy that is dominated by a term proportional to the area of the entangling surface.