Vacuum structure of a scalar field on a torus with uniform magnetic flux

TL;DR

This paper studies the vacuum structure of a complex scalar field on a torus with magnetic flux, revealing critical area effects, multiple vacuum configurations, and symmetry-breaking phenomena.

Contribution

It provides a detailed analysis of vacuum expectation values, degeneracy, and symmetry properties for different magnetic flux values using the lowest-mode approximation.

Findings

Vacuum expectation value becomes nonzero above a critical torus area.

Number of degenerate vacua depends on magnetic flux M.

Vacuum configurations can preserve or break system symmetries.

Abstract

We investigate the vacuum expectation value of a complex scalar field on a two-dimensional torus with quantized magnetic flux $M$. A characteristic feature of this system is the emergence of a critical area: when the area of the torus exceeds this critical value, the vacuum expectation value becomes nonvanishing. Furthermore, any nonzero vacuum expectation value necessarily exhibits nontrivial dependence on the coordinates of the torus. Employing the lowest-mode approximation, we find a single vacuum configuration for $M=1$, whereas two and six degenerate vacuum configurations arise for $M=2$ and $M=3$, respectively. We then analyze the symmetry properties of these vacuum configurations and determine whether they preserve or spontaneously break the symmetry of the underlying system.