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

拟议中的研究是在最基本的层面上理解自然的一部分，从而导致一个单一的、完整的和一致的物理理论。在小距离内，物质和力的行为受量子力学的支配。自从大约40年前标准模型的形成以来，亚原子的电磁力、弱力和强力就已经被理解了。这些力和它们作用的粒子是由量子场论描述的，对于数学一致性来说，标准模型包含大量的对称性是至关重要的。标准模型在实验上取得了惊人的成功，最近在欧洲核子研究中心的大型强子对撞机（LHC）上发现了一个强有力的候选者希格斯玻色子，希格斯玻色子是标准模型预测的最后一个有待发现的粒子。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结合起来，为所有四种力提供一个一致的理论。标准模型也无法解释基础物理中质量尺度的层次、粒子类型的扩散以及宇宙中暗物质的性质。众所周知，暗物质大量存在，但尚未被观测到。人们普遍认为，超对称性，即费米子（如电子）与玻色子（如光子）交换的对称性，将在形成四种力的统一理论中发挥重要作用。超对称预言了尚未观测到的亚原子粒子的存在，而寻找这些粒子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，因此在形成宇宙结构中起着重要作用。标准模型之外的其他物理学理论假设，“基本”粒子实际上是扩展的、复合的物体，或者存在更多维度的空间。弦是沿着一维方向延伸的微观物体，可以振动，就像小提琴上的弦一样。虽然弦和膜的基本理论尚不清楚，但它们在低能量下的作用完全可以用超引力理论来描述，通过研究这些理论，人们已经意识到，被称为膜的物体和被称为对偶的对称性是整个理论的重要组成部分。膜可以被认为是将字符串推广到沿着一个以上维度扩展的对象。值得注意的是，人们发现弦和膜可以在包含重力和标准模型的四维空间中导致一致的量子理论，同时也为超越标准模型的新物理学提供了前景。拟议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精确的确认，但精确计算的数量很少。近年来，人们发现了某些弦理论与四维量子场论之间的对应关系。这导致了前者的新技术能够精确计算物理利益的数量。这是正在进行的研究的一部分，同时探索弦和膜对标准模型之外的物理学的可能后果，并了解大型强子对撞机、天体物理实验和宇宙学揭示的其他新物理学。

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.