标题： 量子引力中时空的消失与出现 显示英文标题

标题： Disappearance and emergence of space and time in quantum gravity

摘要： 我们讨论了在微观尺度下连续空间和时间消失的迹象。这些包括它们具有离散性质的论据，或者是在引力的量子理论中根本非局域性的论据。我们讨论了这些思想如何在特定的量子引力方法中实现。 然后，我们将问题反过来，考虑从离散的、前几何的量子空间的基本单元的集体行为中涌现出来的连续空间和时间，并且将时空理解为某种“凝聚态”，并且提出这种涌现过程是相变的结果，称为“几何发生”。 我们讨论了这个场景以及一般意义上涌现时空的一些概念性问题。 作为一个具体的例子，我们概述了GFT（群场论）的量子引力框架，并展示了在这种框架下时空涌现的一种试探性程序。 最后，我们重新审视了由这个涌现时空场景提出的一些概念性问题，并结合这个具体例子进行分析。 显示英文摘要

摘要： We discuss the hints for the disappearance of continuum space and time at microscopic scale. These include arguments for a discrete nature of them or for a fundamental non-locality, in a quantum theory of gravity. We discuss how these ideas are realized in specific quantum gravity approaches. Turning then the problem around, we consider the emergence of continuum space and time from the collective behaviour of discrete, pre-geometric atoms of quantum space, and for understanding spacetime as a kind of "condensate", and we present the case for this emergence process being the result of a phase transition, dubbed "geometrogenesis". We discuss some conceptual issues of this scenario and of the idea of emergent spacetime in general. As a concrete example, we outline the GFT framework for quantum gravity, and illustrate a tentative procedure for the emergence of spacetime in this framework. Last, we re-examine the conceptual issues raised by the emergent spacetime scenario in light of this concrete example.