Theoretical Physics

该计划的PI将在理论物理学的各种令人兴奋的领域进行研究，包括标准模型的扩展，电弱对称性破缺，量子色动力学，中微子物理学，超对称性，量子场论中的异常和边界条件，共形场论，超弦的量子化，以及弦紧化的几何。量子场论是基本粒子和力的语言。在量子场论中，所谓的标准模型描述了自然界中除了引力之外的已知力，即电磁力、弱力和强力。标准模型没有解决的谜团之一是“世代”问题，即粒子类型的三倍重复。另一个是电弱对称性破缺的起源，或者说弱相互作用是如何变弱的。人们普遍希望，欧洲核子研究中心的大型强子对撞机将在未来几年内开始为这些问题提供质的新见解。事实上，许多扩展标准模型的提议，特别是那些具有超对称性的提议，都有望得到验证。在超对称模型中，已知的粒子都有尚未发现的“伙伴”，它们的存在改善了理论的量子行为。近年来的实验也证实，中微子只通过弱力相互作用，质量很小但不为零，这在标准模型的构建中是没有设想到的。中微子质量对天体物理学和宇宙学也有深远的影响。标准模型中的强力由场论量子色动力学（QCD）描述，这是观测新信号的实验计划的核心。它还展示了量子场论中尚未被理解的关键方面，并呈现了“弱耦合”和“强耦合”行为。在弱耦合或微扰的QCD中的工作既可以预测新物理学的信号，也可以预测它们的背景。研究该理论的强耦合行为是为了理解核子的结构，以及它与其他理论的关系，包括弦论。弦理论是唯一已知的引力的有限量子理论，并且激发了许多对量子场论的新见解，特别是QCD及其超对称扩展。它是统一所有已知力的唯一候选理论。它使人们深入了解黑洞的本质，并揭示了与现代数学许多方面的深刻联系。它提出了许多在LHC上看到的新物理学的建议。拟议中的研究将通过推进我们对自然规律的认识并有助于更好地理解物理宇宙而产生广泛的影响。事实上，高级参与者正在研究的许多主题在媒体上被广泛讨论，例如“幽灵”中微子在宇宙中的作用，以及物理学家对即将投入使用的大型强子对撞机的希望。本建议中概述的研究将用于培训研究生和博士后研究员。该提案的教师经常参与外联工作，以接触更广泛的公众。 其中包括通过邵逸夫系列公开讲座和西蒙斯基金会支持的物理和数学暑期讲习班。他们还参与为研究生编写教科书。

The PIs on this proposal will perform research in a variety of exciting areas in theoretical physics, including extensions of the Standard Model, electroweak symmetry breaking, quantum chromodynamics, neutrino physics, supersymmetry, anomalies and boundary conditions in quantum field theory, conformal field theory, the quantization of the superstring, and the geometry of string compactifications. Quantum field theory is the language of elementary particles and forces. Among quantum field theories, the so-called Standard Model describes the known forces in Nature aside from gravity, namely the electromagnetic, weak and strong forces. Among the mysteries not addressed by the Standard Model is the problem of "generations", a three-fold repetition of particle types. Another is the origin of electroweak symmetry breaking, or precisely how the weak interactions become weak. It is widely hoped that the Large Hadron Collider at CERN will begin providing qualitatively new insights into these issues within the next few years. Indeed, it is expected that many proposals for extensions of the Standard Model, especially those with supersymmetry, will be tested. In supersymmetric models, known particles all have as-yet undetected "partners", whose presence improves the quantum behavior of the theory. Experiments over recent years have also confirmed that neutrinos, which only interact via the weak forces, have small but nonzero masses, not envisioned in the construction of the Standard Model. Neutrinos masses also have profound consequences for astrophysics and cosmology. The strong force in the Standard Model is described by the field theory quantum chromodynamics (QCD), which is central to experimental programs for observing new signals. It also exhibits crucial aspects of quantum field theory that are not yet understood, and presents both "weak coupling" and "strong coupling" behaviors. Work in weak-coupling, or perturbative, QCD serves both to make predictions for signals of new physics and their backgrounds. The strong-coupling behavior of the theory is studied to understand the structure of the nucleons, and for its relation to other theories, including string theory. String theory is the only known finite quantum theory of gravity, and has inspired many new insights into quantum field theories, especially QCD and its supersymmetric extensions. It is the only candidate for a theory that unifies all the known forces. It has given insights into the nature of black holes and revealed profound links to many aspects of modern mathematics. It suggests many proposals for new physics to be seen at the LHC. The proposed research will have a broad impact by advancing our knowledge of the laws on Nature and contributing toward a better understanding of the physical universe. Indeed, many of the topics under study by the senior participants are widely discussed in the media, such as the role of "ghostly" neutrinos in the Universe, and hopes of physicists for the soon-to-be-commissioned Large Hadron Collider. The research outlined in this proposal will serve in the training of graduate students and postdoctoral fellows. The faculty on this proposal are often involved in outreach efforts to reach a broader public. These include public lectures through the Run Run Shaw series and summer workshops in physics and mathematics supported by the Simons foundation. They are also involved in writing textbooks for graduate students.