M-theory, Cosmology and Quantum Field Theory

伦敦帝国理工学院理论物理小组的研究项目集中在量子引力、量子场论和宇宙学等相互关联的基本问题上。我们研究量子引力问题的方法主要来源于超弦理论和超引力，以及这两种方法的假设母体理论，即m理论。我们工作的一个重要目标将是弦理论和非微扰Yang-Mills规范理论之间的关系，这种关系可以用对偶关系和精确可积量子场论模型推导出来。特别是，我们希望获得关于量子弦理论谱以及弦理论与诸如约束等重要杨-米尔斯规范理论现象之间关系的精确信息。弦理论和杨-米尔斯规范理论之间的关系已经发展到可以对诸如夸克-胶子等离子体等系统中的强相互作用物理做出具体物理预测的地步，这可能会在欧洲核子研究中心的大型强子对撞机上进行探索。我们研究的第二个主要目标将是通过扩展我们对相关超重力场方程的显式解的研究来分析弦理论的许多真空状态。已经发现了无限类具有不破缺超对称的解，我们打算将这种理解扩展到这些真空附近理论的谱性质。我们将研究的弦和超引力理论的另一个特征是它们所显示的大量对偶对称性，以及这些对称性如何导致时空几何和量子场相互关联的新型全局解，统称为广义几何。我们在将数值技术应用于弦和超重力解的研究方面也有广泛的专业知识，我们将进一步发展这些技术，并将它们应用于黑洞的性质。在宇宙学和量子场论的相关领域，宇宙大爆炸起源结构的关键线索可以在宇宙微波背景的非高斯修正中找到。这是关于早期宇宙中密度扰动的起源和星系结构形成的重要指示。我们已经参与了普朗克、蜘蛛和BPol等观测项目，也参与了这些数据的分析。另一方面，早期宇宙中量子场的演化及其对早期宇宙结构演化的影响也需要充分发展的模型。因此，在分析观测微波背景数据的同时，我们将追求早期宇宙场动力学和结构形成的计算建模。我们广泛的研究领域之间有着深刻的协同作用，一方面，Yang-Mills规范理论的非摄动方面的工作为超重力和超弦理论提供了信息，另一方面，对早期宇宙高温场的研究和早期宇宙密度波动的计算建模提供了信息。我们的大部分工作都围绕着引力和杨-米尔斯规范理论的问题展开，既有基础层面的，也有宇宙学层面的。

The research programme of the Theoretical Physics Group at Imperial College London is focused on the interrelated fundamental problems of quantum gravity, quantum field theory and cosmology. Our approaches to the problems of quantum gravity derive principally from superstring theory and supergravity and from the hypothesised parent theory of both these approaches known as M-theory. One important target of our work will be the relations between string theory and non-perturbative Yang-Mills gauge theory which can be derived using duality relations and exactly integrable quantum field theory models. In particular, we hope to obtain exact information about the quantum string theory spectrum and the relations between string theory and important Yang-Mills gauge theory phenomena such as confinement. The relations between string theory and Yang-Mills gauge theories have developed to the point where concrete physical predictions can be made about strong interaction physics in systems such as quark-gluon plasmas, which may be explored at the LHC collider at CERN. A second major target of our research will be to analyse the many vacuum states of string theory by extending our work on explicit solutions to the associated supergravity field equations. Infinite classes of such solutions with unbroken supersymmetry have been found, and we intend to extend this understanding to the spectral properties of the theory near these vacua. Another feature of string and supergravity theories which we shall investigate is the large class of duality symmetries they display, and how these lead to new kinds of global solutions where spacetime geometry and quantum fields are interrelated, known collectively as generalised geometry. We also have extensive expertise in the application of numerical techniques to the study of string and supergravity solutions, and we will further develop these and also apply them to the properties of black holes. In the area of cosmology and related aspects of quantum field theory, key clues to the structure of the big bang origin of the universe are to be found in the non-Gaussian corrections to the cosmic microwave background. This is an important indication about the origin of density perturbations in the early universe and of the formation of galactic structures. We have established participation both in observational programmes such as Planck, Spider and BPol, and also in the analysis of this data. On the other hand, fully developed models are needed of the evolution of quantum fields in the early universe and their effect on the evolution of early universe structure. So, in parallel with the analysis of observational microwave background data, we will pursue computational modelling of early-universe field dynamics and structure formation. There is a deep synergy between the broad strands of our research, with work on the non-perturbative aspects of Yang-Mills gauge theories informing both supergravity and superstring theory on the one hand and the study of high-temperature fields in the early universe and the computational modelling of early-universe density fluctuations on the other. Much of our work revolves around the problems of gravity and Yang-Mills gauge theories, both at a fundamental level and also in cosmology.