Quantum broadening of k-strings in gauge theories

TL;DR

This paper investigates how quantum fluctuations cause the flux tube in gauge theories to broaden logarithmically with source separation, revealing a universal behavior across different representations and theories.

Contribution

It introduces a geometric model predicting universal logarithmic broadening of k-strings, confirmed through lattice gauge theory simulations.

Findings

Flux tube cross-section grows logarithmically with separation

Universal slope of broadening across representations and theories

Validation through 3D Z_4 lattice gauge model simulations

Abstract

We study the thickness of the confining flux tube generated by a pair of sources in higher representations of the gauge group. Using a simple geometric picture we argue that the area of the cross-section of the flux tube, as measured by a Wilson loop probe, grows logarithmically with source separation, as a consequence of the quantum fluctuations of the underlying k-string. The slope of the logarithm turns out to be universal, i.e. it is the same for all the representations and all the gauge theories. We check these predictions in a 3D Z_4 lattice gauge model by comparing the broadening of the 1-string and the 2-string.