Lattice gauge theories in the presence of a linear gauge-symmetry breaking

TL;DR

This paper investigates the robustness of gauge invariance in three-dimensional lattice gauge theories with scalar fields under linear gauge-symmetry breaking perturbations, revealing the continuum limit remains gauge-invariant despite small GSB terms.

Contribution

It demonstrates that gauge symmetry in certain lattice models is robust against linear GSB perturbations and maps the phase diagram with various ordered phases and universality classes.

Findings

Gauge invariance persists in the continuum limit despite small GSB perturbations.

The phase diagram includes disordered, tensor, and vector ordered phases with continuous transitions.

Transitions belong to O(3), O(4), and O(2) universality classes, meeting at a multicritical point.

Abstract

We study the effects of gauge-symmetry breaking (GSB) perturbations in three-dimensional lattice gauge theories with scalar fields. We study this issue at transitions in which gauge correlations are not critical and the gauge symmetry only selects the gauge-invariant scalar degrees of freedom that become critical. A paradigmatic model in which this behavior is realized is the lattice CP(1) model or, more generally, the lattice Abelian-Higgs model with two-component complex scalar fields and compact gauge fields. We consider this model in the presence of a linear GSB perturbation. The gauge symmetry turns out to be quite robust with respect to the GSB perturbation: the continuum limit is gauge-invariant also in the presence of a finite small GSB term. We also determine the phase diagram of the model. It has one disordered phase and two phases that are tensor and vector ordered, respectively. They are separated by continuous transition lines, which belong to the O(3), O(4), and O(2) vector universality classes, and which meet at a multicritical point. We remark that the behavior at the CP(1) gauge-symmetric critical point substantially differs from that at transitions in which gauge correlations become critical, for instance at transitions in the noncompact lattice Abelian-Higgs model that are controlled by the charged fixed point: in this case the behavior is extremely sensitive to GSB perturbations.