New Ideas in Gauge, String and Lattice Theory (Transfer)

粒子物理学的标准模型编码了我们目前对原子基本成分和大爆炸后最早时刻物质性质的认识。然而，我们对标准模型动力学的理解受到我们解决其强相互作用部分的能力的限制，量子色动力学（QCD）描述了夸克和胶子的相互作用。斯旺西集团和普利茅斯集团正从两个互补的角度处理这一问题。通过将时空的连续近似为离散的点格，可以在高性能计算机上模拟QCD。该小组将研究大爆炸后存在的高温和密度的极端条件下的晶格QCD，现在可以在欧洲核子研究中心的大型强子对撞机（LHC）的重离子碰撞中实现。这些研究将得到“规范-引力对偶性”的分析见解的补充，这是一个将描述粒子物理学的理论与广义相对论性质联系起来的重要原理，然而，大型强子对撞机的主要目标是发现负责基本粒子质量产生的新物理学。这种“电弱对称性破缺”是标准模型中最不为人所知的部分。这可能是因为存在一个贯穿时空的背景场，当粒子与背景场相互作用时，背景场给了粒子质量。另一方面，质量的产生可能是因为存在一个新的强相互作用，这个新的强相互作用是由大型强子对撞机探测到的。在这两种情况下，理论预测存在一种新的自旋为零的粒子，即最近在大型强子对撞机上发现的著名的希格斯玻色子。区分这些可能性是一个微妙的问题，我们再一次试图用规范引力对偶和晶格模拟来解决这个问题，然而，粒子物理学家并不相信标准模型是自然界的终极理论。它是规范理论的一个例子，规范理论是一个理论框架，它将量子力学和狭义相对论与物理学家通过几十年的粒子加速器实验发现的基本对称性统一在一起。与此同时，引力仍然在这个框架之外，被广义相对论用时空的曲率来描述。更深层次的统一似乎可以用超弦来实现，超弦包含了规范理论和引力，以及一种被称为超对称的新型时空对称。因此，斯旺西小组正在通过研究规范场和弦的更深层次结构来补充其对LHC物理学的研究，使用规范引力对偶性和“量子可积性”等基本思想来寻找我们当前粒子物理学理论背后的基本原理。

The standard model of particle physics encodes our current knowledge of the fundamental constituents of atoms and the nature of matter in the earliest moments following the Big Bang. However, our understanding of the dynamics of the standard model is limited by our ability to solve its strongly-interacting sector, quantum chromodynamics (QCD), which describes the interactions of quarks and gluons. The Swansea and Plymouth groups are approaching this problem from two complementary perspectives. By approximating the continuum of spacetime as a discrete lattice of points, it is possible to simulate QCD on high performance computers. The groups will study lattice QCD in the extreme conditions of high temperature and density which existed following the Big Bang and which can now be realised in heavy-ion collisions at the Large Hadron Collider (LHC) at CERN. These investigations will be complemented by analytic insights arising from `gauge- gravity duality', a remarkable principle which relates the theories describing particle physics with properties of general relativity.The primary goal of the LHC is, however, to discover the new physics which is responsible for the generation of mass for the elementary particles. This `electroweak symmetry breaking' is the least understood part of the standard model. It may be due to the existence of a background field permeating spacetime, which gives mass to particles as they interact with it. On the other hand, mass generation may be due to the existence of a new strong interaction at the TeV energy scale probed by the LHC. In both cases, the theories predict the existence of a new spin zero particle, the famous Higgs boson recently discovered at the LHC. Distinguishing these possibilities is a subtle problem and once again we are attempting to resolve the question using both gauge-gravity duality and lattice simulations.Particle physicists do not, however, believe that the standard model is the ultimate theory of nature. It is an example of a gauge theory, a theoretical framework which unifies quantum mechanics and special relativity together with the fundamental symmetries which physicists have discovered through decades of experiments with particle accelerators. Meanwhile, gravity remains outside this framework, being described by general relativity in terms of the curvature of spacetime. A deeper unification appears possible with superstrings, which contain both gauge theories and gravity together with a new type of spacetime symmetry known as supersymmetry. The Swansea group is therefore complementing its investigations of LHC physics with research into the deeper structure of gauge fields and strings, using fundamental ideas such as gauge-gravity duality and `quantum integrability' in the search for the underlying principles behind our current theories of particle physics.