Fermion Bags, Duality, and the Three Dimensional Massless Lattice Thirring Model

The recently proposed fermion-bag approach is a powerful technique to solve some four-fermion lattice field theories. Because of 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 v = 0.85(1), eta = 0.65(1), and eta(psi) = 0.37(1).