2020/09/30 by Simon Hands, Michele Mesiti, Jude Worthy · 1 citation
Physics and Astronomy · #hep-lat #hep-th
paper · pdf · doi:10.1103/physrevd.102.094502
published as Phys. Rev. D 102, 094502 (2020) · 25 pages, 16 figures, a reference added and 2 figure captions amended
arxiv created 2020/11/07 · arxiv updated 2021/10/11
Results of a lattice field theory simulation of the single-flavor Thirring model in 2+1 spacetime dimensions are presented. The lattice model is formulated using domain wall fermions as a means to recover the correct U(2) symmetries of the continuum model in the limit where wall separation Ls→∞. Simulations on 123, 163× Ls, varying self-interaction strength g2 and bare mass m are performed with Ls = 8, … 48, and the results for the bilinear condensate ⟨ψψ⟩ fitted to a model equation of state assuming a U(2)→U(1)⊗U(1) symmetry-breaking phase transition at a critical gc2. First estimates for g-2a and critical exponents are presented, showing small but significant departures from mean-field values. The results confirm that a symmetry-breaking transition does exist and therefore the critical number of flavors for the Thirring model Nc > 1. Results for both condensate and associated susceptibility are also obtained in the broken phase on 163×48, suggesting that here the Ls→∞ extrapolation is not yet under control. We also present results obtained with the associated 2+1d truncated overlap operator DOL demonstrating exponential localisation, a necessary condition for the recovery of U(2) global symmetry, but that recovery of the Ginsparg-Wilson condition as Ls→∞ is extremely slow in the broken phase.