Effects of a Thermal Bath of Photons on Embedded String Stability

TL;DR

This paper investigates how thermal photons influence the stability of embedded pion strings in the linear sigma model of QCD, showing that thermal effects can stabilize otherwise unstable string configurations.

Contribution

It demonstrates that thermal photon corrections can stabilize embedded string solutions in field theories, extending understanding of defect stabilization mechanisms.

Findings

Thermal photons induce effective potential terms stabilizing pion strings.

Embedded strings can be stabilized at temperatures below confinement.

Results applicable to other embedded defect configurations like electroweak Z-strings.

Abstract

We compute the corrections of thermal photons on the effective potential for the linear sigma model of QCD. Since we are interested in temperatures lower than the confinement temperature, we consider the scalar fields to be out of equilibrium. Two of the scalar field are uncharged while the other two are charged under the U(1) gauge symmetry of electromagnetism. We find that the induced thermal terms in the effective potential can stabilize the embedded pion string, a string configuration which is unstable in the vacuum. Our results are applicable in a more general context and demonstrate that embedded string configurations arising in a wider class of field theories can be stabilized by thermal effects. Another well-known example of an embedded string which can be stabilized by thermal effects is the electroweak Z-string. We discuss the general criteria for thermal stabilization of embedded defects.