Quantum Gravity and Entanglement

量子引力和纠缠

• 批准号: 1404204
• 负责人: Eugenio Bianchi
• 金额: $ 15万
• 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: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1404204&HistoricalAwards=false
• 关键词: Quantum; Gravity; Entanglement

Entanglement, the unique property of quantum mechanics that prevents the description of a system by just looking at the properties of its individual components, is a centerpiece in current research in diverse areas of physics spanning from quantum information science to condensed matter physics to quantum field theory. The main objective of this research is to understand the role of entanglement in the description of the quantum nature of space-time. This works investigates fundamental puzzles in theoretical physics such as the description of the primordial state of the universe and the fate of information in black hole evaporation. The focus is on universal aspects of space-time entanglement that can provide valuable insights for any theory of quantum gravity. At the Planck scale new quantum effects that go beyond Einstein's general relativity are expected to dominate. Loop quantum gravity is one of the leading candidate theories for describing the physics in these regimes. In this theory, space-time has a granular structure that arises as a foam-like excitation of a topologically invariant vacuum. From this perspective, space-time is made of 'elementary constituents' and, as in condensed matter physics, it can have different quantum phases. The main open problem is to identify the quantum phase that describes our smooth extended space-time. A set of techniques that were recently developed in condensed matter physics will be used to study the amount of entanglement between quantum geometry degrees of freedom. This research will directly address the question of the quantum nature of space-time. The results of this research on entangled-network states will provide the basis for extracting physical properties of space-time states in quantum gravity. Three directions will be investigated. The first regards the Minkowski space-time state where the entangled-network state is obtained via a variational ansatz for the minimization of the ADM energy. The second direction regards the use of entangled-network states in quantum cosmology, the study of entanglement near classical singularities, and the thermalization time of subsystems in the de Sitter expansion phase. The third direction regards black hole space-times, the relation between entanglement entropy and black hole entropy, and the dynamics of entanglement entropy in the evaporation process.

纠缠是量子力学的独特性质，它阻止了仅仅通过观察单个组件的性质来描述系统，是当前物理学各个领域研究的核心，从量子信息科学到凝聚态物理学再到量子场论。这项研究的主要目的是了解纠缠在描述时空量子性质中的作用。这部作品探讨了理论物理学中的基本难题，例如宇宙原始状态的描述和黑洞蒸发中信息的命运。重点是时空纠缠的普遍方面，可以为任何量子引力理论提供有价值的见解。在普朗克尺度下，超越爱因斯坦广义相对论的新量子效应预计将占主导地位。圈量子引力是描述这些区域物理的主要候选理论之一。在这个理论中，时空具有粒状结构，它是拓扑不变真空的泡沫状激发。从这个角度来看，时空是由“基本成分”组成的，就像在凝聚态物理学中一样，它可以有不同的量子相位。主要的开放问题是确定描述我们光滑扩展时空的量子相位。 最近在凝聚态物理学中开发的一套技术将用于研究量子几何自由度之间的纠缠量。这项研究将直接解决时空的量子性质问题。对纠缠网络态的研究结果将为量子引力中时空态物理性质的提取提供基础。将从三个方面进行研究。第一个是关于闵可夫斯基时空状态，其中纠缠网络状态是通过变分方法获得的ADM能量的最小化。第二个方向是在量子宇宙学中使用纠缠网络状态，研究经典奇点附近的纠缠，以及德西特膨胀阶段子系统的热化时间。第三个方向涉及黑洞时空、纠缠熵与黑洞熵的关系以及纠缠熵在蒸发过程中的动力学。

项目成果

Loop expansion and the bosonic representation of loop quantum gravity

环展开和环量子引力的玻色子表示

• DOI: 10.1103/physrevd.94.086009
• 发表时间: 2016
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Bianchi, E.;Guglielmon, J.;Hackl, L.;Yokomizo, N.
• 通讯作者: Yokomizo, N.

Entanglement entropy of squeezed vacua on a lattice

晶格上压缩真空的纠缠熵

• DOI: 10.1103/physrevd.92.085045
• 发表时间: 2015
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Bianchi, Eugenio;Hackl, Lucas;Yokomizo, Nelson
• 通讯作者: Yokomizo, Nelson

Entanglement time in the primordial universe

原始宇宙中的纠缠时间

• DOI: 10.1142/s021827181544006x
• 发表时间: 2015
• 期刊: International Journal of Modern Physics D
• 影响因子: 2.2
• 作者: Bianchi, Eugenio;Hackl, Lucas;Yokomizo, N.
• 通讯作者: Yokomizo, N.

Entanglement entropy production in gravitational collapse: covariant regularization and solvable models

引力塌缩中的纠缠熵产生：协变正则化和可解模型

• DOI: 10.1007/jhep06(2015)180
• 发表时间: 2015
• 期刊: Journal of High Energy Physics
• 影响因子: 5.4
• 作者: Bianchi, Eugenio;De Lorenzo, Tommaso;Smerlak, Matteo
• 通讯作者: Smerlak, Matteo