标题： 物质驱动的时空拓扑变化 显示英文标题

标题： Matter-driven change of spacetime topology

摘要： 利用蒙特卡洛计算机模拟，我们研究了物质场对基于CDT模型的典型量子宇宙几何的影响。这个量子宇宙的大小约为几个普朗克长度，并且具有三维环面的空间拓扑结构。物质场是多分量标量场，在每个空间方向上取值于周长为$\delta$的环面上，该环面作为CDT模型中的新参数。通过改变$\delta$，我们观察到由标量场引起的相变。这一发现可能对具有非平凡拓扑的量子宇宙有重要意义，因为相变可以将拓扑结构变为单连通的。 显示英文摘要

摘要： Using Monte-Carlo computer simulations, we study the impact of matter fields on the geometry of a typical quantum universe in the CDT model of lattice quantum gravity. The quantum universe has the size of a few Planck lengths and the spatial topology of a three-torus. The matter fields are multi-component scalar fields taking values in a torus with circumference $\delta$ in each spatial direction, which acts as a new parameter in the CDT model. Changing $\delta$, we observe a phase transition caused by the scalar field. This discovery may have important consequences for quantum universes with non-trivial topology, since the phase transition can change the topology to a simply connected one.