标题： 量子叠加态中的粒子探测器在德西特时空中的表现 显示英文标题

标题： Particle detectors in superposition in de Sitter spacetime

摘要： 宇宙学粒子产生是时空膨胀导致该时空中某种量子场的粒子产生的现象。 在本文中，我们通过考虑一个在德西特时空中的多级量子粒子探测器，并将其与无质量实量子标量场耦合来研究这一现象。 而不是考虑探测器的固定经典轨迹，根据最近的新方法，我们考虑轨迹的量子叠加，特别是保持彼此固定距离的静态轨迹。 主要的新结果是，由于轨迹叠加的量子性质，探测器与场相互作用后的状态不仅是从每个单独静态轨迹预期的热态的混合态，而是由于不同轨迹之间的干涉表现出额外的相干性。 我们详细研究了这些现象，并将它们与探测器从热浴中吸收的粒子的特性联系起来。 显示英文摘要

摘要： Cosmological particle creation is the phenomenon by which the expansion of spacetime results in the production of particles of a given quantum field in that spacetime. In this paper, we study this phenomenon by considering a multi-level quantum particle detector in de Sitter spacetime coupled to a massless real quantum scalar field. Rather than considering a fixed classical trajectory for the detector, following recent novel approaches we consider a quantum superposition of trajectories, in particular of static trajectories which keep a fixed distance from one another. The main novel result is that, due to the quantum nature of the superposition of trajectories, the state of the detector after interaction with the field is not only a mixture of the thermal states that would be expected from each individual static trajectory but rather exhibits additional coherences due to interferences between the different trajectories. We study these in detail and associate them with the properties of the particle absorbed by the detector from the thermal bath.