Phase Transitions in Abelian Lattice Gauge Theory: Production and Dissolution of Monopoles and Monopole-Antimonopole Pairs

TL;DR

This paper uses a microcanonical approach to analyze phase transitions in U(1) lattice gauge theory, identifying multiple higher-order transitions related to monopole and monopole-antimonopole pair dynamics.

Contribution

It combines microcanonical formulations and inflection point analysis to systematically characterize and distinguish multiple phase transitions in lattice electrodynamics.

Findings

Identifies a first-order deconfinement phase transition due to monopole pair dissolution.

Detects two independent third-order phase transitions in the confined phase.

Associates third-order transitions with monopole defect formation and pair production.

Abstract

We combine the microcanonical formulation of lattice gauge theories (LGTs) developed by Callaway and the microcanonical inflection point analysis (MIPA) proposed by Bachmann et al. to achieve a systematic characterization of phase transitions (PTs) in U(1) lattice electrodynamics. Besides identifying the well-known deconfinement PT (DPT) due to the neutral pair dissolution, which we classify as a first-order PT, we unequivocally detect three higher-order PTs. According to MIPA, we observe two independent third-order PTs in the confined phase; instead, in the deconfined (Coulomb) phase, we observe a dependent third-order PT. For a deeper understanding of the physical meaning of these PTs, we numerically compute the average number density of monopolar and pair defects as a function of energy. Our analysis reveals that DPT is only one of the major mechanisms observable in LGT. The independent third-order PTs are associated, respectively, to the first occurrence of monopolar topological defects and to the production of pairs.