Fermion bags, duality and the three dimensional massless lattice Thirring model

TL;DR

This paper introduces a fermion bag approach that enables efficient Monte Carlo simulations of the three-dimensional massless lattice Thirring model, accurately determining critical exponents near the quantum critical point.

Contribution

The paper presents a novel fermion bag method that effectively handles strong and weak coupling regimes, allowing precise computation of critical phenomena in the 3D lattice Thirring model.

Findings

Critical exponents: ν=0.85(1), η=0.65(1), η_ψ=0.37(1)

Efficient Monte Carlo algorithms for both coupling limits

First accurate computation near the quantum critical point

Abstract

The recently proposed fermion bag approach is a powerful technique to solve some four-fermion lattice field theories. Due to the existence of a duality between strong and weak couplings, the approach leads to efficient Monte Carlo algorithms in both these limits. The new method allows us for the first time to accurately compute quantities close to the quantum critical point in the three dimensional lattice Thirring model with massless fermions on large lattices. The critical exponents at the quantum critical point are found to be $\nu=0.85(1)$, $\eta = 0.65(1)$ and $\eta_\psi = 0.37(1)$.