Effective Descriptions of Quantum Gravity and Cosmology

量子引力和宇宙学的有效描述

• 批准号: 1607414
• 负责人: Martin Bojowald
• 金额: $ 27万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1607414&HistoricalAwards=false
• 关键词: Effective; Descriptions; Quantum; Gravity; Cosmology

General relativity and quantum mechanics are the two major theories that govern fundamental physics, of space-time and of elementary particles. However, it is not known how they could be combined to a consistent theory of quantum gravity. Fascinating phenomena such as the very first stages of the big bang or the cores of black holes therefore remain out of the reach of our current understanding. This project investigates a wide range of systems in which both general relativity and quantum mechanics are relevant. The main interest is given by methods that allow one to derive physical implications by approximations, and to use the results to guide the developments of quantum gravity. Applications to the big bang and black holes often lead to conclusions that capture the interest of the general public. Related methods can also be used in systems not involving general relativity, where they may help to solve technical questions or to communicate results in a new way, supporting for instance the teaching of quantum mechanics.The objective of this project is to introduce and evaluate new methods for a systematic analysis of physical implications of one set of candidate theories of quantum gravity, based on canonical quantization. Throughout physics, a powerful tool to derive potentially observable phenomena is given by effective theories which provide quantum corrections to the classical equations. Such systems can more easily be evaluated, analytically or numerically, than equations for quantum states and thus are more direct sources for the discovery of new phenomena. While standard techniques to derive effective equations do not apply to canonical quantum gravity, a general scheme applicable to canonical quantum theories exists (introduced by the PI) and is used in this project to address the main problems of quantum gravity. It provides the basis for a long-term program evaluating physical phenomena in the broad context of quantum gravity. Such a systematic derivation will make it possible to put effects found previously in simplified models on a firm footing, uncover new phenomena and provide reliable predictions. Results will be used to compare the theory with other candidates of quantum gravity, with the potential of a fruitful transfer of ideas and techniques between the approaches.

广义相对论和量子力学是支配时空和基本粒子的基础物理学的两个主要理论。然而，我们不知道如何将它们结合到一个相容的量子引力理论中。因此，像大爆炸的第一阶段或黑洞的核心这样的快速现象仍然超出了我们目前的理解范围。该项目研究了广义相对论和量子力学都相关的各种系统。主要的兴趣是通过方法，允许一个近似导出的物理含义，并使用结果来指导量子引力的发展。应用于大爆炸和黑洞的研究，往往会得出能引起公众兴趣的结论。相关的方法也可以用于不涉及广义相对论的系统，在那里它们可能有助于解决技术问题或以新的方式交流结果，例如支持量子力学的教学。本项目的目标是介绍和评估新方法，用于系统分析一组基于正则量子化的量子引力候选理论的物理含义。在整个物理学中，有效的理论提供了一个强大的工具来推导潜在的可观察现象，这些理论为经典方程提供了量子修正。这样的系统可以更容易地评估，分析或数值，比量子态方程，因此是发现新现象的更直接的来源。虽然导出有效方程的标准技术不适用于正则量子引力，但存在适用于正则量子理论的一般方案（由PI引入），并在本项目中用于解决量子引力的主要问题。它为在量子引力的广泛背景下评估物理现象的长期计划提供了基础。这种系统的推导将使人们有可能把以前在简化模型中发现的效应建立在坚实的基础上，发现新的现象并提供可靠的预测。结果将被用来比较理论与其他候选人的量子引力，与一个富有成效的转移的想法和技术的方法之间的潜力。