The Schwinger Model on the lattice in the Microcanonical Fermionic Average approach

TL;DR

This paper applies the Microcanonical Fermionic Average method to the Schwinger Model on the lattice, successfully studying its phase space and accurately recovering the continuum chiral condensate result.

Contribution

It demonstrates the applicability of the Microcanonical Fermionic Average method to an asymptotically free theory, enabling efficient exploration of parameter space and precise measurement of physical quantities.

Findings

Recovered continuum chiral condensate within 3 decimal places

Validated the method's effectiveness for asymptotically free theories

Studied the entire parameter space at negligible computational cost

Abstract

The Microcanonical Fermionic Average method has been used so far in the context of lattice models with phase transitions at finite coupling. To test its applicability to Asymptotically Free theories, we have implemented it in QED$_2$, \it i.e.\rm the Schwinger Model. We exploit the possibility, intrinsic to this method, of studying the whole $\beta, m$ plane at negligible computer cost, to follow constant physics trajectories and measure the $m \to 0$ limit of the chiral condensate. We recover the continuum result within 3 decimal places.