Theory of antihydrogen atoms.

我们的世界是由物质构成的。它的基石是原子。原子又由质子、中子和电子等粒子组成。每一个粒子都有一个镜像--反粒子。反粒子的电荷和磁矩与普通粒子相反，但据我们所知，除此之外它们是相同的。就像粒子构成物质一样，反物质也可以由反粒子构成。但反粒子并不是自然存在的，当它们遇到普通物质时，迟早会湮灭。最简单的反原子，反氢，最近在欧洲核子研究中心的两个实验中被创造出来，ATHENA和ATRAP。这些实验的目的是将反氢储存在原子阱中，以便研究其详细性质。虽然反物质被认为是物质的完美镜像，但这只在一定的精度范围内是真实的。如果在镜像中发现任何微小的缺陷，这将对我们理解基础物理学和宇宙学产生深远的影响。也许它可以解释物质和反物质之间非常明显的不对称性;我们只能看到我们周围的物质。该项目旨在推进对反氢的理论理解，以支持实验。迄今为止形成的反氢原子还不能用于详细的研究。一个原因是原子几乎没有结合在一起。为了进行测量，它们需要被带到它们最紧密的束缚态：它们的量子力学基态。另一个原因是反原子太热了。必须找到冷却它们或在较低温度下直接形成它们的方法。这些都是我打算用量子力学计算来解决的问题。我还将研究物质和反物质之间的相互作用。在单个原子与反原子的碰撞中，湮灭只是几种可能的结果之一。原子和反原子也可能再次弹开而不湮灭，或者可能形成新的系统，例如核-反核和电子-反电子。甚至可以形成原子-反原子分子，尽管寿命非常有限。原子与反原子的碰撞在许多方面与普通原子之间的碰撞不同，并且更难以计算。一个全新的特征是强大的核力，它会导致湮灭，但也会影响其他过程。另一个区别是原子核和反核具有相反的电荷，这意味着它们相互吸引，而普通的原子核在碰撞中从不靠近。因此，传统原子物理学的许多概念发生了变化，必须发展新的理论方法。在这里，我将与迈克尔查尔顿教授的实验组一起工作。这个小组是ATHENA合作的一部分，它首先产生了冷反氢，现在是ATHENA的继任者阿尔法的一部分。

Our world is made of matter. Its building stones are atoms. Atoms in turn are made of particles: protons, neutrons, and electrons. For every particle there is a mirror image - an antiparticle. The charge and magnetic moment of an antiparticle is opposite that of an ordinary particle, but otherwise they are, as far as we know, the same. Just as particles build up matter, antimatter can be built by antiparticles. But antiparticles do not exists naturally, they will sooner or later annihilate when they meet ordinary matter.The simplest antiatom, antihydrogen, has recently been created in two experiments, ATHENA and ATRAP, at CERN. The goal of these experiment is to store antihydrogen in an atom trap, so that its detailed properties can be studied. Although antimatter is believed to be a perfect mirror image of matter, this is only known to be true within a certain precision. If any small flaw could be found in the mirror image, this would have profound consequences for our understanding of fundamental physics and cosmology. Perhaps it could explain a very obvious asymmetry between matter and antimatter; we only see matter around us.This project aims to advance the theoretical understanding of antihydrogen, in order to support the experiments. The antihydrogen atoms formed so far cannot be used for detailed studies. One reason is that the atoms are just barely bound together. In order to make measurements they need to be brought to their most tightly bound state: their quantum mechanical ground state. Another reason is that the antiatoms are too hot. Methods have to be found to either cool them, or to form them directly at lower temperatures. These are problems I intend to address using quantum mechanical calculations.I will also study the interaction between matter and antimatter. In a single atom-antiatom collision annihilation is only one of several possible outcomes. The atom and antiatom may also bounce apart again without annihilating, or new systems may be formed, e.g. nucleus-antinucleus and electron-antielectron. Even an atom-antiatom molecule could be formed, although with a very limited lifetime. Atom-antiatom collisions are in many ways different, and more difficult to calculate, than collisions between ordinary atoms. A completely new feature is the strong nuclear force, which causes annihilation, but also has an influence on other processes. Another difference is that the nucleus and antinucleus have opposite electric charge, which means that they attract each other, contrary to ordinary nuclei which never approach close to each other in collisions. Therefore many concepts from traditional atomic physics are changed, and new theoretical methods must be developed.The research will be undertaken at the University of Wales, Swansea. Here I will work together with the experimental group of Prof. Michael Charlton. This group was part of the ATHENA collaboration which first produced cold antihydrogen, and is now part of ATHENA:s successor ALPHA.