More on the continuum limit of gauge-fixed compact U(1) lattice gauge theory

TL;DR

This paper investigates the continuum limit of 4D compact U(1) lattice gauge theory, providing evidence of a continuous phase transition at large couplings and exploring the interplay with fermionic matter.

Contribution

It confirms previous proposals about the continuum limit and characterizes the phase transition and photon recovery in the gauge-fixed lattice U(1) theory.

Findings

Evidence of a continuous phase transition at large couplings

Identification of a chiral transition with fermions at high gauge couplings

Locating the critical region where free photons emerge

Abstract

We have verified various proposals that were suggested in our last paper concerning the continuum limit of a compact formulation of the lattice U(1) pure gauge theory in 4 dimensions using a nonperturbative gauge-fixed regularization. Our study reveals that most of the speculations are largely correct. We find clear evidence of a continuous phase transition in the pure gauge theory at "arbitrarily" large couplings. When probed with quenched staggered fermions with U(1) charge, the theory clearly has a chiral transition for large gauge couplings whose intersection with the phase transition in the pure gauge theory continues to be a promising area for nonperturbative physics. We probe the nature of the continuous phase transition by looking at gauge field propagators in the momentum space and locate the region on the critical manifold where free photons can be recovered.