Induced Magnetic moments in three-dimensional gauge theories with external magnetic fields

TL;DR

This paper investigates how external magnetic fields induce parity-violating magnetic moments in three-dimensional gauge theories with multiple fermion species, using a model relevant to high-temperature superconductors.

Contribution

It demonstrates the induction of parity-violating magnetic moments via Landau level decomposition in a SU(2)xU(1) gauge model, linking theory to superconducting phenomena.

Findings

Induced magnetic moments arise from higher Landau levels in the effective theory.

Parity violation is linked to fermion mass and Landau level structure.

Relevance to observed phenomena in high-temperature superconductors.

Abstract

We study the appearance of induced parity-violating magnetic moment, in the presence of external magnetic fields, for even-number of fermion species coupled to dynamical fields in three dimensions. Specifically, we use a SU(2)xU(1) gauge model for dynamical gauge symmetry breaking, which is also proposed recently as a field theoretical model for high-temperature superconductors. By decomposing the fermionic degrees of freedom in terms of Landau levels, we show that, in the effective theory with the lowest Landau levels, a parity-violating magnetic moment interaction is induced by the higher Landau levels when the fermions are massive. The possible relevance of this result for a recently observed phenomenon in high-temperature superconductors is also discussed.