标题： 关于de Sitter时空量子叠加退相干的局域计算札记 显示英文标题

标题： Note on the local calculation of decoherence of quantum superpositions in de Sitter spacetime

摘要： 我们研究了由于宇宙视界的存在，量子叠加态在de Sitter（dS）时空中的退相干效应。利用弯曲时空中量子场论的代数方法，我们推导出标量场情况下纠缠粒子预期数目的确切表达式。该表达式建立了退相干与局域两点关联函数之间的关系。具体而言，我们分析了位于dS时空中心的局域观测者所执行的量子叠加思想实验。我们计算了标量场、电磁场以及引力场情形下的纠缠粒子数目。结果表明，量子空间叠加态可以通过向宇宙视界发射纠缠粒子而发生退相干。我们的设定等价于5维闵可夫斯基时空中作加速运动的观测者。标量场和电磁场的结果与文献[1]中加速观测者在闵可夫斯基时空中的结果一致，该文献从加速观测者的角度研究了退相干效应。然而，我们的结果修正了引力退相干的数值因子。 显示英文摘要

摘要： We study the decoherence effect of quantum superposition in de Sitter (dS) spacetime due to the presence of the cosmological horizon. Using the algebraic approach of quantum field theory on curved spacetime, we derive the precise expression for the expected number of entangling particles in the scalar field case. This expression establishes the relation between the decoherence and the local two-point correlation function. Specifically, we analyze the quantum superposition Gendankenexperiment performed by a local observer at the center of dS spacetime. We compute the entangling particle numbers in scalar field, electromagnetic field, and gravitational field scenarios. It is demonstrated that the quantum spatial superposition state can be decohered by emitting entangling particles into the cosmological horizon. Our setup is equivalent to an accelerating observer in 5-dimensional Minkowski spacetime. The results for the scalar and electromagnetic cases are consistent with those obtained in Ref.[1], which investigated the decoherence effect from the perspective of an accelerating observer in Minkovski spacetime. However, our result fixes the numerical prefactor of the gravitational decoherence.