Density Matrix Renormalization Group Approach to the Massive Schwinger Model

TL;DR

This paper applies the density matrix renormalization group method to the massive Schwinger model, achieving highly accurate results for lattice sizes up to 256 sites and confirming theoretical predictions about phase transitions and particle behavior.

Contribution

It introduces a DMRG approach to the lattice Schwinger model, significantly improving accuracy and confirming key theoretical predictions about phase transitions and particle properties.

Findings

High-accuracy estimates in the continuum limit

Confirmation of Coleman's 'half-asymptotic' particles

Localization of the phase transition in the 2D Ising universality class

Abstract

The massive Schwinger model is studied, using a density matrix renormalization group approach to the staggered lattice Hamiltonian version of the model. Lattice sizes up to 256 sites are calculated, and the estimates in the continuum limit are almost two orders of magnitude more accurate than previous calculations. Coleman's picture of `half-asymptotic' particles at background field (theta = pi) is confirmed. The predicted phase transition at finite fermion mass (m/g) is accurately located, and demonstrated to belong in the 2D Ising universality class.