Dyon electric charge and fermion fractionalization

TL;DR

This paper calculates quantum corrections to dyon electric charge in N=2 gauge theories, revealing how fermion fractionalization causes discontinuities in the dyon spectrum and ensuring consistency with semi-classical monodromies.

Contribution

It provides a first principles calculation of quantum corrections to dyon charges for arbitrary gauge groups, including the effects of fermion fractionalization.

Findings

Quantum corrections depend discontinuously on the moduli space.

Discontinuities occur on co-dimension one curves where dyons decay.

The dyon spectrum at weak coupling matches semi-classical monodromies.

Abstract

A first principles calculation of the quantum corrections to the electric charge of a dyon in an N=2 gauge theory with arbitrary gauge group is presented. These corrections arise from the fermion fields via the mechanism of fermion fractionalization. For a dyon whose magnetic charge is a non-simple co-root, the correction is a discontinuous function on the moduli space of vacua and the discontinuities occur precisely on co-dimension one curves on which the dyon decays. In this way, the complete spectrum of dyons at weak coupling is found for a theory with any gauge group. It is shown how this spectrum is consistent with the semi-classical monodromies.