Particles, Fields and Spacetime

宇宙中的所有物质和除了引力之外的基本力似乎都可以用粒子理论很好地描述，在粒子理论中，物质的基本成分是点状粒子，它们通过交换其他种类的粒子而相互作用。量子场论是描述这些粒子理论的数学语言;描述力的粒子由一类称为规范理论的理论描述。然而，我们似乎需要超越量子场论，把引力包括在内。这个扩展的主要候选者是弦理论，它基于这样的想法，即粒子实际上是一维的弦环，相互作用由连接不同弦的光滑表面描述。我们的研究之一是开发量子场论计算的新工具。在一个研究领域中，人们已经认识到某些规范理论具有额外的先前未被怀疑的对称性，这解释了某些计算结果的神秘简单性。这是为了获得更有效的计算技术，越来越普遍的问题。在一条独立的线上，一种叫做共形对称的对称性被新利用来限制粒子的含量和具有这种对称性的理论的相互作用。我们的目标是进一步开发这些工具，并将它们与完全解决最简单，最对称的理论的长期目标结合在一起。我们还对远离真空的场论方面进行了广泛的研究，包括对光滑经典解（孤子）及其模空间的研究，以及场论的特殊类别，其中理论是完全可解的（可积模型）。弦理论的研究发现，某些量子场论可以在更多维的空间中与弦理论联系起来;这被称为全息术。场论中的一些困难问题可以映射到高维空间中的简单问题。这也为弦理论提供了一个新的视角，可以用来加深我们对引力的理解。我们正在研究这些技术的应用领域的理论，用来研究有趣的新阶段的问题，我们正在探索的作用，内在的量子力学功能的场论中出现的高维几何。宇宙学是对早期宇宙的研究。这与粒子理论有着长期的富有成效的相互作用，我们正在进一步发展这一点，将场论的新发展与宇宙学观测联系起来。例如，我们正在研究最近在欧洲核子研究中心发现的希斯玻色子在宇宙演化中的作用。

All matter in the universe and the fundamental forces apart from gravity appear to be well described by particle theories, in which the fundamental components of matter are pointlike particles, which interact by exchanging other kinds of particles. Quantum field theory is the mathematical language describing these particle theories; the particles describing forces are described by a class of theories called gauge theories. However, it appears we need to go beyond quantum field theory to include gravity. The leading candidate for this extension is string theory, which is based on the idea that the particles are actually one-dimensional loops of string, with the interactions described by smooth surfaces connecting different strings. One strand of our research is the development of new tools for computations in quantum field theory. In one line of research, it has been understood that certain gauge theories have additional previously unsuspected symmetries, which explain the mysterious simplicity of some computational results. This has been developed to obtain more efficient calculational techniques for increasingly general questions. In an independent line, a symmetry called conformal symmetry has been newly exploited to constrain the particle content and interactions of theories with this symmetry. We aim to develop these tools further and bring them together with the long-term goal of completely solving the simplest, most symmetric theories. We also have a broad programme of research on aspects of field theory far from the vacuum, including work on smooth classical solutions (solitons) and their moduli spaces, and special classes of field theories where the theory is completely solvable (integrable models). Work on string theory has led to the discovery that some quantum field theories can be related to string theories in a space with more dimensions; this is referred to as holography. Some difficult questions in the field theory can be mapped to simpler questions in the higher-dimensional space. This also provides a new perspective on string theory, which can be used to deepen our understanding of gravity. We are studying the application of these techniques to field theories used to study interesting new phases of matter, and we are exploring the role of intrinsically quantum mechanical features of the field theory in the emergence of the higher-dimensional geometry. Cosmology is the study of the very early universe. This has a long history of fruitful interaction with particle theory, and we are developing this further, relating new developments in field theory to cosmological observations. For example, we are studying the role of the Hiss boson recently discovered at CERN in cosmological evolution.