Lattice Hamiltonian approach to the Schwinger model: further results from the strong coupling expansion

TL;DR

This paper applies exact diagonalization with strong coupling expansion to the Schwinger model, providing highly precise results for ground state energy, scalar mass gap, and chiral condensate, and analyzing flux loop effects.

Contribution

It introduces improved precision calculations for the Schwinger model using a lattice Hamiltonian approach with strong coupling expansion.

Findings

Ground state energy and scalar mass gap calculated with 10^{-9} accuracy

Chiral condensate oscillations linked to flux loops

Comparison with previous literature confirms results

Abstract

We employ exact diagonalization with strong coupling expansion to the massless and massive Schwinger model. New results are presented for the ground state energy and scalar mass gap in the massless model, which improve the precision to nearly $10^{-9} %$. We also investigate the chiral condensate and compare our calculations to previous results available in the literature. Oscillations of the chiral condensate which are present while increasing the expansion order are also studied and are shown to be directly linked to the presence of flux loops in the system.