标题： 轴子-德西特宇宙中的关系动力学 显示英文标题

标题： Relational dynamics in axion-de Sitter universes

摘要： 我们研究在存在轴子物质的渐近德西特宇宙中，根据一对动力学参考系（即观察者）的协变，一维余维最大体积及相关几何可观测量的演化。这会生成一个欧几里得虫洞，纠缠两个宇宙，从而改变时空拓扑结构。系统通过切分一个欧几里得虫洞制备成两份拷贝的哈特尔-霍金态。我们推导了每个宇宙中锚定在世界线参考框架的一维余维可观测量的演化。我们研究轴子电荷如何在可观测量的演化中与宇宙常数竞争。对于低轴子电荷，最大体积几乎呈指数增长，而对于德西特空间允许的最大轴子电荷，最大体积则减少到零。 显示英文摘要

摘要： We study the evolution of codimension-one maximal volume and related geometric observables according to a pair of dynamical reference frames (i.e. observers) in asymptotically de Sitter universes in the presence of axion matter. This sources a Euclidean wormhole entangling the two universes, thereby changing the spacetime topology. The system is prepared in a two-copy Hartle-Hawking state by slicing a Euclidean wormhole. We derive the evolution of codimension-one observables anchored to the worldline reference frame in each universe. We investigate how the axion charge competes with the cosmological constant in the evolution of the observables. The maximal volume increases nearly exponentially for low axion charge, while it decreases to a vanishing value for the maximal axion charge allowed by de Sitter space.