Density of States of the lattice Schwinger model

TL;DR

This paper applies a tensor network method to analyze the density of states in the lattice Schwinger model, revealing parameter regimes with symmetric spectra and exploring thermodynamic properties.

Contribution

It introduces a tensor network approach to study the spectral density of the lattice Schwinger model, highlighting finite-size and lattice spacing effects.

Findings

Spectral symmetry and continuum properties observed at certain parameters.

Asymmetric spectral density appears at moderate system sizes and lattice spacing.

Method can be used to extract thermodynamic quantities.

Abstract

Using a recently introduced tensor network method, we study the density of states of the lattice Schwinger model, a standard testbench for lattice gauge theory numerical techniques, but also the object of recent experimental quantum simulations. We identify regimes of parameters where the spectrum appears to be symmetric and displays the expected continuum properties even for finite lattice spacing and number of sites. However, we find that for moderate system sizes and lattice spacing of $ga\sim O(1)$, the spectral density can exhibit very different properties with a highly asymmetric form. We also explore how the method can be exploited to extract thermodynamic quantities.