Tensor network formulation of the massless Schwinger model

TL;DR

This paper develops a tensor network approach to model the massless Schwinger model on a lattice, enabling the inclusion of topological terms and accurate phase diagram calculations.

Contribution

It introduces a tensor network formulation for the massless Schwinger model, incorporating topological terms and applying HOTRG for phase diagram analysis.

Findings

Good agreement with hybrid Monte Carlo results

Successful inclusion of topological term in tensor network

Accurate phase diagram computation

Abstract

We construct a tensor network representation of the partition function for the massless Schwinger model on a two dimensional lattice using staggered fermions. The tensor network representation allows us to include a topological term. Using a particular implementation of the tensor renormalization group (HOTRG) we calculate the phase diagram of the theory. For a range of values of the coupling to the topological term $\theta$ and the gauge coupling $\beta$ we compare with results from hybrid Monte Carlo when possible and find good agreement.