A two-component picture of the <A^2> condensate with instantons

TL;DR

This paper investigates the relationship between the <A^2> condensate and instantons in non-Abelian gauge theory, combining analytical and model-based approaches to understand their interplay and contributions to the condensate.

Contribution

It introduces a two-component picture of the <A^2> condensate, utilizing the Local Composite Operators formalism and instanton liquid model for quantitative analysis.

Findings

Analytical computation of <A^2> condensate using Local Composite Operators.

Partial resolution of the infrared problem in instanton physics.

Quantitative assessment of condensate contributions in the instanton liquid model.

Abstract

We study the interplay between the <A^2> condensate and instantons in non-Abelian gauge theory. Therefore we use the formalism of Local Composite Operators, with which the vacuum expectation value of this condensate can be analytically computed. We first use the dilute gas approximation and partially solve the infrared problem of instanton physics. In order to find quantitative results, however, we turn to an instanton liquid model, where we find how the different contributions to the condensate add up.