Theta Vacua in the Light-Cone Schwinger Model

TL;DR

This paper explores how theta vacua manifest in the light-cone quantized Schwinger model, analyzing gauge choices and their impact on the chiral condensate's theta dependence.

Contribution

It provides a detailed analysis of theta vacua in the light-cone Schwinger model, comparing gauge choices and their effects on physical observables.

Findings

Theta vacuum manifestations depend on gauge choice.

Chiral condensate exhibits theta dependence in both gauges.

Different gauge fixings lead to distinct physical Hilbert spaces.

Abstract

We discuss the bosonized Schwinger model in light-cone quantization, using discretization as an infrared regulator. We consider both the light-cone Coulomb gauge, in which all gauge freedom can be removed and a physical Hilbert space employed, and the light-cone Weyl (temporal) gauge, in which the Hilbert space is unphysical and a Gauss law operator is used to select a physical subspace. We describe the different ways in which the theta vacuum is manifested depending on this choice of gauge, and compute the theta-dependence of the chiral condensate in each case.