From supersymmetry, strings and branes to the LHC and cosmology.

这项拟议的研究是在最基本的层面上理解自然的探索的一部分，导致了一个单一、完整和一致的物理学理论。在很小的距离内，物质和力的行为受量子力学的支配。自从大约40年前标准模型提出以来，人们对亚原子电磁力、弱电磁力和强电磁力的认识已经有了很大进展。这些力和它们作用的粒子是由量子场论描述的，标准模型包含了大量的对称性，这对数学一致性至关重要。标准模型在实验上取得了巨大的成功，最近在欧洲核子研究中心的大型强子对撞机(LHC)上发现了希格斯玻色子的有力候选者，这是标准模型预测的最后一种仍未发现的粒子。我们目前对引力的描述是爱因斯坦非常成功的广义相对论，它描述了行星、恒星、星系以及整个宇宙的运动。不幸的是，广义相对论与量子力学不一致，因此不能简单地与标准模型相结合，提供关于所有四种力的一致理论。标准模型也未能解释基础物理中质量尺度的等级、粒子类型的扩散以及宇宙中暗物质的性质。人们普遍认为，超对称性将在形成四力统一理论方面发挥重要作用。超对称性是费米子(如电子)与玻色子(如光子)交换的对称性。超对称性预示着尚未观测到的亚原子粒子的存在，而对这些粒子的探索是建造大型强子对撞机背后的一个重要动机。其中之一实际上可能是暗物质，因此在宇宙结构的形成中扮演着重要角色。其他超越标准模型的物理学理论假设，基本粒子实际上是延伸的复合物体，或者空间有更多维度。弦是沿着一个维度延伸的微观物体，可以振动，就像小提琴上的琴弦。尽管弦和膜的基本理论尚不为人所知，但它们在低能量下的效应完全由超引力理论描述，通过对这些理论的研究，人们已经认识到，物体，称为膜，和对称性，称为对偶，是完整理论的重要组成部分。膜可以被认为是沿着多个维度延伸的对象的字符串的泛化。值得注意的是，人们发现弦和膜可以在包含引力和标准模型的四个维度上产生一致的量子理论，同时也为超越标准模型的新物理提供了前景。拟议的研究的一部分旨在发现和理解弦和膜的基本理论。尽管量子场论在理论和实验上都取得了惊人的成功，导致了理论和实验之间最准确的确认，但准确计算出来的量很少。近年来，人们发现了某些弦理论与量子场论在四个维度上的对应关系。这导致了前者的新技术，使之能够准确地计算物理兴趣的量。这是正在进行的研究的一部分，以及探索弦和膜对超越标准模型的物理的可能后果，并了解大型强子对撞机、天体物理实验和宇宙学正在揭示的其他新物理。

The proposed research is part of a quest to understand Nature at its most fundamental level, leading to a single, complete and consistent theory of physics. At small distances, the behaviour of matter and forces is governed by quantum mechanics. The subatomic electromagnetic, weak and strong forces have been understood since the formulation of the Standard Model some 40 years ago. These forces and the particles they act upon are described by quantum field theory, and it is crucial for mathematical consistency that the Standard Model incorporates a large amount of symmetry. The Standard Model has enjoyed spectacular experimental success, culminating in the recent discovery at the Large Hadron Collider (LHC) at CERN of a strong candidate to be the Higgs Boson, the last particle predicted by the Standard Model that remained to be found.Our current description of gravity is Einstein's very successful theory of General Relativity, which describes the motion of planets, stars and galaxies as well as the Universe as a whole. Unfortunately, General Relativity is not consistent with quantum mechanics and so cannot be simply combined with the Standard Model to provide a consistent theory of all the four forces. The Standard Model also fails to explain the hierarchy of mass scales in fundamental physics, the proliferation of particle types and the nature of the dark matter in the Universe, which is known to be present in large quantities but has not yet been seen.It is widely believed that supersymmetry, which is a symmetry that exchanges fermions (such as the electron) with bosons (such as the photon), will play an important role in formulating a unified theory of the four forces. Supersymmetry predicts the existence of yet unobserved subatomic particles, and the search for these was an important motivation behind the construction of the LHC. One of them could in fact be dark matter, and hence play an important role in forming structures in the universe. Other theories of physics beyond the Standard Model postulate that 'elementary' particles are in fact extended, composite objects, or that there are more dimensions of space.Strings are microscopic objects that are extended along one dimension and can vibrate, rather like strings on a violin. Although the underlying theory of strings and branes is not known, their effects at low energies are completely described by supergravity theories, and by studying these it has been realized that objects, called branes, and symmetries, called dualities, are important parts of the full theory. Branes can be thought of as generalizations of strings to objects that are extended along more than one dimension. Remarkably, one finds that strings and branes can lead to consistent quantum theories in four dimensions that contain gravity as well as the Standard Model, while also offering prospects for novel physics beyond the Standard Model.Part of the proposed research aims to find and understand this underlying theory of string and branes. Although quantum field theories have had spectacular theoretical and experimental success, leading to the most accurately known confirmation between theory and experiment, there are very few quantities which have been computed exactly. In recent years, a correspondence between certain string theories and quantum field theories in four dimensions has been found. This has led to new techniques in the former that enable the exact computation of quantities of physical interest. This is part of the ongoing research, as well as exploring the possible consequences of strings and branes for physics beyond the Standard Model, and understanding what other new physics is being revealed by the LHC, astrophysical experiments and cosmology.