近日，德国法兰克福大学的Peter Lowdon及其研究团队取得一项新进展。经过不懈努力，他们对有限温度下微扰理论的一致性进行研究。相关研究成果已于2024年8月21日在国际知名学术期刊《高能物理杂志》上发表。
在本文中，研究人员使用大规模?4理论中标量相关函数的格点模拟来分析这些约束在多大程度上影响微扰预测。研究人员发现，即使在相对较低的温度下不存在红外发散，标准的微扰预测也会恶化，而这与展开式中使用的传播子的解析结构直接相关。
这表明，在传播子中纳入非微扰热效应对于有限温度下标量量子场论的一致微扰表述至关重要。研究人员通过利用对有限温度相关函数施加的光谱约束，探讨了这些效应如何在格点数据中体现，并讨论了不同热粒子激发态的存在为何为解决这些问题提供了潜在途径。
据悉，在有限温度下，微扰法处理量子场理论时的一个众所周知的难题是，必须解决在真空理论中不存在的理论约束。
附：英文原文
Title: On the (in)consistency of perturbation theory at finite temperature
Author: Lowdon, Peter, Philipsen, Owe
Issue&Volume: 2024-08-21
Abstract: A well-known difficulty of perturbative approaches to quantum field theory at finite temperature is the necessity to address theoretical constraints that are not present in the vacuum theory. In this work, we use lattice simulations of scalar correlation functions in massive ?4 theory to analyse the extent to which these constraints affect the perturbative predictions. We find that the standard perturbative predictions deteriorate even in the absence of infrared divergences at relatively low temperatures, and that this is directly connected to the analytic structure of the propagators used in the expansion. This suggests that the incorporation of non-perturbative thermal effects in the propagators is essential for a consistent perturbative formulation of scalar quantum field theories at finite temperature. By utilising the spectral constraints imposed on finite-temperature correlation functions, we explore how these effects manifest themselves in the lattice data, and discuss why the presence of distinct thermoparticle excitations provides a potential resolution to these issues.
DOI: 10.1007/JHEP08(2024)167
Source: https://link.springer.com/article/10.1007/JHEP08(2024)167