Nonperturbative physics in sigma models

西格玛模型中的非微扰物理

• 批准号: 332396356
• 负责人: Dr. Falk Bruckmann
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/332396356?language=en
• 关键词: Nonperturbative; physics; sigma; models

Two-dimensional sigma models are prominent strongly coupled systems sharing asymptotic freedom, a dynamically generated mass-gap and other important properties with Quantum chromodynamics. Recently, two very interesting nonperturbative effects have been studied in these systems: the cancellation of perturbative renormalon singularities by fractional instanton contributions and the generation of a nonzero charge density by a chemical potential through a formulation in terms of dual variables. Both topics shall be advanced in this project, mainly using lattice techniques. Discretisations on space-time lattices are one of the very few ab initio approaches to nonperturbative physics. The project aims at checking the renormalon conjecture in these models numerically as well as further developing dual variables for structural questions and specific simulations at nonzero density and beyond.

二维 sigma 模型是突出的强耦合系统，与量子色动力学共享渐近自由度、动态生成的质量间隙和其他重要属性。最近，在这些系统中研究了两种非常有趣的非微扰效应：通过分数瞬时子贡献消除微扰重整奇点，以及通过双变量公式通过化学势生成非零电荷密度。这两个主题都将在本项目中得到推进，主要使用格子技术。时空晶格的离散化是非微扰物理的极少数从头算方法之一。该项目旨在以数值方式检验这些模型中的重整猜想，并进一步开发用于结构问题的双变量以及非零密度及以上的特定模拟。