Probing the ground state in gauge theories

TL;DR

This paper compares string and Coulombic models of flux tubes linking heavy quarks in gauge theories, revealing phase-dependent accuracy and differences between abelian and non-abelian cases.

Contribution

It provides a comparative analysis of flux tube models in different phases and gauge theories, highlighting the effectiveness of Coulombic and string descriptions.

Findings

String description better in confined phase (U(1))

Coulombic description better in deconfined phase (U(1))

Coulombic description superior in both phases for non-abelian theories

Abstract

We consider two very different models of the flux tube linking two heavy quarks: a string linking the matter fields and a Coulombic description of two separately gauge invariant charges. We compare how close they are to the unknown true ground state in compact U(1) and the SU(2) Higgs model. Simulations in compact U(1) show that the string description is better in the confined phase but the Coulombic description is best in the deconfined phase; the last result is shown to agree with analytical calculations. Surprisingly in the non-abelian theory the Coulombic description is better in both the Higgs and confined phases. This indicates a significant difference in the width of the flux tubes in the two theories.