Precision study of the massive Schwinger model near quantum criticality

TL;DR

This paper uses advanced numerical methods to precisely analyze the massive Schwinger model near criticality, achieving high-accuracy critical mass calculations and exploring effects of model deformations.

Contribution

It provides the most accurate critical mass determination for the massive Schwinger model using DMRG and compares multiple criticality criteria for consistency.

Findings

Critical mass computed to five digits accuracy

Perfect agreement among four criticality criteria

Effect of four-fermion deformation on critical mass analyzed

Abstract

We perform a numerical analysis of the massive Schwinger model in the presence of a background electric field. Using the Density Matrix Renormalization Group (DMRG) approach, we efficiently compute the spectrum of the Schwinger model on a staggered lattice with up to 3000 qubits. As a result, we achieve a precise computation of the critical mass of the massive Schwinger model to five digits using four different 'criticality criteria', observing perfect agreement among them. Additionally, we discuss the effect of a four-fermion operator deformation of the Schwinger model and compute the critical mass for various values of the deformation parameter.