CDT - an Entropic Theory of Quantum Gravity
CDT - an Entropic Theory of Quantum Gravity
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CDT - 量子引力熵理论
DOI：
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发表时间：
2010
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通讯作者：
R. Loll
中科院分区：
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作者：
J. Ambjorn;A. Goerlich;J. Jurkiewicz;R. Loll
在这些讲座中，我们描述了如何根据基于所谓因果动态三角测量（CDT）的晶格公式来构建量子引力理论。我们讨论如何获得连续统极限以及如何定义和测量微分同胚不变相关器。在我们主要感兴趣的四个维度中，晶格理论具有红外极限，可以用德西特时空来识别。我们解释了为什么量子时空的这种红外特性是不平凡的，并且是由于非微扰路径积分测量中编码的“熵”效应。这使得德西特宇宙的出现成为微观量子定律中经典性真正出现的一个例子。我们还讨论了紫外线行为的重要方面，并展示了如何研究新兴背景几何形状周围的量子涨落。最后，我们考虑与渐近安全场景的联系，并从中推导出 CDT 量子引力中新的、推测的标度关系。
In these lectures we describe how a theory of quantum gravity may be constructed in terms of a lattice formulation based on so-called causal dynamical triangulations (CDT). We discuss how the continuum limit can be obtained and how to define and measure diffeomorphism-invariant correlators. In four dimensions, which has our main interest, the lattice theory has an infrared limit which can be identified with de Sitter spacetime. We explain why this infrared property of the quantum spacetime is nontrivial and due to "entropic" effects encoded in the nonperturbative path integral measure. This makes the appearance of the de Sitter universe an example of true emergence of classicality from microscopic quantum laws. We also discuss nontrivial aspects of the UV behaviour, and show how to investigate quantum fluctuations around the emergent background geometry. Finally, we consider the connection to the asymptotic safety scenario, and derive from it a new, conjectured scaling relation in CDT quantum gravity.