Using Monte Carlo computer simulations, we study the impact of matter fields on the geometry of a typical quantum universe in the causal dynamical triangulations (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 multicomponent 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 nontrivial topology, since the phase transition can change the topology to a simply connected one.

中文翻译：

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时空拓扑的物质驱动变化

使用蒙特卡罗计算机模拟，我们在晶格量子引力的因果动力学三角剖分 ( cdt ) 模型中研究了物质场对典型量子宇宙几何形状的影响。量子宇宙有几个普朗克长度的大小和三环面的空间拓扑结构。物质场是多分量标量场，在圆周环面中取值$\delta$在每个空间方向上，它作为cdt模型中的一个新参数。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产生重要影响，因为相变可以将拓扑改变为简单连接的拓扑。