Dual simulation of the massless lattice Schwinger model with topological term and non-zero chemical potential

TL;DR

This paper presents a dual simulation approach for the massless lattice Schwinger model incorporating a topological term and chemical potential, effectively solving the complex action problem and enabling detailed analysis of the model's phase structure.

Contribution

It introduces a novel dual representation for the model that allows efficient simulation with a topological term and chemical potential, overcoming previous computational challenges.

Findings

Successful implementation of dual simulation method

Validation against conventional and exact methods

Insights into the model's physical behavior

Abstract

We discuss simulation strategies for the massless lattice Schwinger model with a topological term and finite chemical potential. The simulation is done in a dual representation where the complex action problem is solved and the partition function is a sum over fermion loops, fermion dimers and plaquette-occupation numbers. We explore strategies to update the fermion loops coupled to the gauge degrees of freedom and check our results with conventional simulations (without topological term and at zero chemical potential), as well as with exact summation on small volumes. Some physical implications of the results are discussed.