Non-perturbative and out-of-equilibrium field theories

物理学家对强相互作用的物理系统非常感兴趣。主要原因是量子色动力学(QCD)，这一在核水平上支配亚原子粒子相互作用的理论，具有很强的相互作用。多年来，人们已经知道QCD的这种性质导致了核物质的许多不寻常和有趣的性质。然而，由几代物理学家开发的标准计算技术，主要是在量子电动力学(QED)的背景下开发的，不适用于强耦合系统。出于这个原因，人们对这些系统的行为知之甚少。在过去的10-20年里，布鲁克海文国家实验室和欧洲核子研究中心开发了涉及粒子加速器的昂贵的实验计划，以对强耦合系统进行经验研究。夸克胶子等离子体是在相对论核碰撞中产生的，最近出现了许多令人兴奋的实验结果。由于被研究的系统在其演化开始时在一段未知的时间内处于不平衡状态，这使得对这些结果的解释变得更加困难。*对科学的进步来说，理论家跟上实验计划的步伐是很重要的。因此，最近在强耦合和非平衡系统中计算可观测性的理论技术的发展方面有了很大的进展。这项工作既难又令人兴奋。它涉及到发明完全不同的数学方法来描述以前被认为超出了我们数学描述能力的物理情况。我的研究计划的一个目标是发展一种特殊的非微扰形式(称为n粒子不可约作用量)，并将其应用于强耦合量子场理论。另一个主要目标是开发技术来了解等离子体不稳定性的动态作用。

Physicists are very interested in physical systems that are strongly interacting. The main reason is that quantum chromodynamics (QCD), the theory that governs the interactions of subatomic particles on a nuclear level, is strongly interacting. It has been known for years that this property of QCD is responsible for many of the unusual and interesting properties of nuclear matter. ******However, the standard calculational techniques that have been developed by generations of physicists, largely in the context of quantum electro-dynamics (QED), are not applicable to strongly coupled systems. For this reason, the behavior of these systems is much less well understood. ******Over the past 10-20 years, expensive experimental programs involving particle accelerators have been developed, for example at Brookhaven National Laboratory and CERN, to study strongly coupled systems empirically. Quark gluon plasmas are produced in relativistic nuclear collisions, and many exciting experimental results have recently become available. The interpretation of these results is made even more difficult by the fact that the systems that are studied are out of equilibrium for an unknown period of time at the beginning of their evolution. ******It is important for the progress of science that theorists keep pace with experimental programs. Accordingly, there has been much recent work on the development of theoretical techniques to calculate observables in strongly coupled and non-equilibrated systems. This work is both difficult and exciting. It involves the invention of completely different mathematical methods to describe physical situations that were previously considered beyond our ability to describe mathematically. One goal of my research program is the development of a particular non-perturbative formalism (which is called the n-particle irreducible action), and its application to strongly coupled quantum field theories. Another major goal is the development of techniques to understand the dynamical role of plasma instabilities.