Theoretical Investigations in Classical and Quantum Gravity

该项目旨在为引力物理学的多个领域做出重大贡献。主题范围从理解引力波探测器（如NSF的激光干涉引力波天文台（LIGO）和欧洲处女座）观测到的信号，到研究黑洞的性质和宇宙的起源。与过去由NSF赠款的研究一样，这些结果可能会成为跨学科会议的亮点，加强不同社区之间的沟通。这项拨款资助的研究也将增加STEM学科的人力资源，因为博士后和学生将获得各种技能，包括先进的计算和建模技术。这项拨款资助的研究将涵盖以下主要主题：（i）引力波。LIGO最近的发现为我们打开了一扇全新的宇宙之窗。 拟议研究中的第一组项目将为我们居住的具有暗能量的加速宇宙的现实背景下引力波的产生和传播奠定基础。(ii)第二组项目将侧重于黑洞的量子力学性质。在广义相对论的经典世界中，黑洞是物质、能量和信息的汇。但它们会通过量子辐射蒸发。人们普遍认为能量在这个过程中是守恒的，但关于信息是否仍然丢失，或者它是否完全编码在发射的量子辐射中，一直存在争论。这项正在进行的NSF资助支持的先前工作强烈表明，量子引力效应将消除黑洞中心的“奇点”，从而为信息（似乎在那里丢失）清除道路。 这一进程的细节将得到制定。(iii)第三个项目涉及非常早期的宇宙。在目前公认的宇宙学范式中，量子物理学在宇宙的早期阶段是不可或缺的，然而，此后不久，人们习惯于假设宇宙的行为是经典的，就像广义相对论一样。 这种经典行为是如何出现的，以及为什么量子物理的所有微妙和复杂性都可以被忽略，无论是从基础原因还是从连接理论与观测的角度来看，都是非常有趣的问题。他们将使用弯曲时空中的量子场论，早期宇宙动力学方程和量子力学几何公式的组合方法来解决。(iv)以上讨论的所有三个项目都对从事哲学和物理科学前沿，特别是广义相对论，宇宙学和量子物理学的研究人员非常感兴趣。 该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will aim at making significant contributions to several areas within gravitational physics. The topics range from understanding the signals observed by gravitational wave detectors such as NSF's Laser Interferometric Gravitational Wave Observatory (LIGO) and the European Virgo, to studying the nature of black holes and the origin of the Universe. As with the past research supported by ongoing NSF grants, these results are likely to feature as highlights in interdisciplinary conferences, enhancing communication between diverse communities. Research funded by this grant will also add to human resources in STEM disciplines since post-docs and students will acquire diverse skills, including advanced computational and modeling techniques.Research supported by this grant will cover the following main themes: (i) Gravitational waves. Recent discoveries at LIGO have opened a brand new window on the universe. The first set of projects in the proposed research will lay down foundations for production and propagation of gravitational waves in the realistic context of the accelerating universe with dark energy, which we inhabit. (ii) A second set of projects will focus on quantum mechanical properties of black holes. In the classical world of general relativity, black holes are sinks of matter, energy and information. But they evaporate through emission of quantum radiation. There is a general agreement that energy is conserved in this process but there has been an ongoing debate on whether information is still lost, or if it is fully encoded in the quantum radiation that is emitted. Previous work supported by this ongoing NSF grant strongly suggests that quantum gravity effects will remove the `singularity' at the center of the black hole, thereby clearing the way for information --that appeared to be lost there-- to come out. Details of this process will be worked out. (iii) The third project involves the very early universe. In the currently accepted cosmological paradigms, quantum physics is indispensable in the very early phase of the universe, and yet, soon thereafter it is customary to assume that the universe behaves classically, as in general relativity. How this classical behavior can emerge, and why all the subtleties and intricacies of quantum physics can be ignored, are issues of great interest both for foundational reasons and for bridging theory with observations. They will be addressed using a combination of methods from quantum field theory in curved space-times, equations governing dynamics of the early universe and geometric formulation of quantum mechanics. (iv) All three projects discussed above are of deep interest to researchers working at the interface of philosophy and frontiers of physical science, particularly general relativity, cosmology and quantum physics. The results will be discussed at conferences and workshops in these fields, and serve to train young scientists and philosophers in both disciplines.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.