# The 39th International Symposium on Lattice Field Theory (Lattice 2022)

Aug 8 – 13, 2022
Hörsaalzentrum Poppelsdorf
Europe/Berlin timezone

## Massless Schwinger model with a 4-fermi-interaction at topological angle $\theta = \pi$

Aug 8, 2022, 6:10 PM
20m
CP1-HSZ/1st-1.001 - HS5 (CP1-HSZ)

### CP1-HSZ/1st-1.001 - HS5

#### CP1-HSZ

50
Oral Presentation Theoretical Developments and Applications beyond Particle Physics

Dominic Hirtler

### Description

We study the massless Schwinger model with an additional 4-fermi interaction and a topological term. For topological angle $\theta = \pi$ charge conjugation is implemented in a non-trivial way and we study its spontaneous breaking. We use staggered fermions and the Villain action for the gauge fields, where the topological term is an integer and charge conjugation at $\theta = \pi$ is an exact symmetry. The complex action problem is overcome by a suitable worldline/worldsheet representation. We find that as a function of the 4-fermi coupling the system has a critical point where charge conjugation is broken spontaneously and we present first results on the nature of the critical point.

### Primary authors

Dominic Hirtler Christof Gattringer (Austrian Science Fund FWF and University of Graz, Austria)