Free energy of an SU(2) monopole-antimonopole pair

TL;DR

This study numerically investigates the free energy of monopole-antimonopole pairs in SU(2) gauge theory, revealing screening behavior in both confining and deconfined phases and highlighting the role of glueball excitations.

Contribution

It provides the first high-statistics numerical analysis of monopole-antimonopole free energy in SU(2) theory across different phases, showing screening effects and their relation to glueball states.

Findings

Screened monopole-antimonopole potential in both phases

Screening mass approximately twice the lightest glueball mass at low temperature

Screening mass increases at high temperature

Abstract

We present a high-statistic numerical study of the free energy of a monopole-antimonopole pair in pure SU(2) theory. We find that the monopole-antimonopole interaction potential exhibits a screened behavior, as one would expect in presence of a monopole condensate. Screening occurs both in the low-temperature, confining phase of the theory, and in the high-temperature deconfined phase, with no evidence of a discontinuity of the screening mass across the transition. The mass of the object responsible for the screening at low temperature is approximately twice the established value for the lightest glueball, indicating a prevalent coupling to glueball excitations. At high temperature, the screening mass increases. We contrast the behavior of the quantum system with that of the corresponding classical system, where the monopole-antimonopole potential is of the Coulomb type.