Superstring Theory, Gravitational Instantons and Black Hole Physics

该奖项支持来自贝鲁特美国大学（AUB）的Wafic Sabra的研究。在标准模型内基本粒子相互作用的统一成功之后，理论物理学中最紧迫的问题从此就是量子力学定律与广义相对论的统一，以及在统一理论中将量子引力与其他基本力结合起来。超弦理论是统一量子引力与其他自然力的相容有限理论的主要候选者。超弦的现象学可能与黑洞、粒子物理和宇宙学研究中遇到的问题有关。近年来，出现了一种新的图像，指出存在一个基本理论，M理论。如果有一个小参数，许多理论表现得很好，因为人们可以在这个参数下微扰展开并做出合理的预测。 这个新的基本理论在微扰水平上表现得像弦理论，但在没有小参数的非微扰水平上，它有一个丰富的对称结构，把弦理论的微扰方面与非微扰状态联系起来。该项目将研究这些理论中的引力背景，重点是更高维背景中的黑洞。 所提出的研究的跨学科性质将使其有利于物理学家和数学家在弦理论和微分几何相关领域的工作。它还将有助于在物理和数学研究生课程在AUB的发展，并在向学生介绍研究的前沿，特别是在高能物理的各个领域。M理论在微扰水平上表现得像弦理论，但在非微扰水平上具有丰富的对偶对称结构，将微扰激发与孤子态联系起来。 一个主要的发展是反德西特空间上的弦理论和生活在这些空间边界上的某些超共形杨-米尔斯规范理论之间的等价性。这种等价性使反德西特组态的引力研究更加重要，因为它们为粒子物理学中重要的量子规范场论的研究提供了工具。萨布拉支持的研究的主要重点是：a）研究和分类各种时空维度中的超对称和非超对称引力背景，特别是在规范超引力模型中寻找黑环。B）研究引力瞬子及其与可积模型、爱因斯坦-外尔结构和高维黑洞的关系，以及用弦和M理论解释欧几里德超引力解。c）我们对弦论基础的非微扰理论的理解的发展，并将其纳入弦论对引力物理学、粒子物理学和宇宙学的唯象意义的研究中。

This award supports the research of Wafic Sabra, from the American University of Beirut (AUB).After the success of the unification of the fundamental particle interactions within the standard model, the most pressing question in theoretical physics has since been the unification of the laws of quantum mechanics with the theory of general relativity, as well as the incorporation of quantum gravity with the other fundamental forces in a unified theory. Superstring theory is the leading candidate for a consistent finite theory unifying quantum gravity with the other forces of nature. The phenomenology derived from superstrings may have relevance to the problems encountered in the study of the black holes, particle physics and cosmology. In recent years, a new picture has emerged pointing to the existence of a fundamental theory, M-theory. Many theories behave very nicely if there is a small parameter, since one can perturbatively expand in this parameter and make sensible predictions. This new fundamental theory behaves like string theory at the perturbative level, but at the nonperturbative level, in which there are no small parameters, it has a rich structure of symmetries connecting perturbative aspects of string theory to nonperturbative states. This project will study gravitational backgrounds in these theories, focusing on black holes in higher numbers of dimensional backgrounds. The interdisciplinary nature of the proposed research will make it of benefit to both physicists and mathematicians working in fields related to string theory and differential geometry. It will also help in the development of the graduate programs in physics and mathematics at AUB, and in introducing students to the frontiers of research, particularly in the various fields of high energy physics. M-theory behaves like string theory at the perturbative level, but at the nonperturbative level has a rich structure of duality symmetries connecting perturbative excitations to solitonic states. A major development is the equivalence between string theory on anti-de Sitter spaces and certain superconformal Yang-Mills gauge theories living on the boundary of these spaces. This equivalence gave more importance to the study of gravitational anti-de Sitter configurations as they provide a tool to the study of quantum gauge field theories important for particle physics. The main focus of Sabra's supported research is: a) The study and the classification of supersymmetric and non-supersymmetric gravitational backgrounds in various spacetime dimensions and in particular the search for black rings in gauged supergravity models. b)The study of gravitational instantons and their relation to integrable models, Einstein--Weyl structures and black holes in higher dimensions as well as the interpretation of Euclidean supergravity solutions in terms of string and M-theory. c) The development of our understanding of the nonperturbative theory underlying string theory, and incorporating this in the study of the phenomenological implications of string theory to gravitational physics, particle physics and cosmology