"Light from chaos" in two dimensions

TL;DR

This study uses Monte Carlo simulations to analyze the two-dimensional gauged XY-model, confirming that at weak coupling it behaves like a pure gauge theory without massless states, and discusses implications for chiral lattice gauge theories.

Contribution

It provides numerical evidence supporting the decoupling of gauge symmetry breaking terms at small coupling in the 2D gauged XY-model.

Findings

Long-distance physics matches pure gauge theory at small coupling

No evidence of massless states near critical coupling

Supports use of gauged XY-models in chiral gauge theories

Abstract

We perform a Monte-Carlo study of the lattice two-dimensional gauged XY-model. Our results confirm the strong-coupling expansion arguments that for sufficiently small values of the spin-spin coupling the ``gauge symmetry breaking" terms decouple and the long-distance physics is that of the unbroken pure gauge theory. We find no evidence for the existence, conjectured earlier, of massless states near a critical value of the spin-spin coupling. We comment on recent remarks in the literature on the use of gauged XY-models in proposed constructions of chiral lattice gauge theories.