Bonn 2020 – scientific programme
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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik
MP 9: Quantum Field Theory
MP 9.1: Talk
Wednesday, April 1, 2020, 11:15–11:35, H-HS VII
Absence of chiral symmetry breaking in Thirring models in 1+2 dimensions — •Julian Lenz, Björn Wellegehausen, and Andreas Wipf — Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
The Thirring model is an interacting fermion theory with current-current interaction. The model in 1+2 dimensions has applications in condensed-matter physics to describe the electronic excitations of Dirac materials. Earlier investigations suggest that a critical number of (reducible) flavors Nc exists, below which chiral symmetry can be broken spontaneously. While values for Nc found in the literature vary broadly, recent lattice studies with chiral fermions have indicated that chiral symmetry is unbroken for all integer flavor numbers. To find an accurate value Nc we study the Thirring model for analytically continued N between 0.5 and 1.1. We see no chiral symmetry breaking in all Thirring models with 1 or more flavors of (4-component) fermions. Besides the transition to the unphysical lattice artifact phase we find strong evidence for a hitherto unknown phase transition that exists for N>Nc and should answer the question of where to construct a continuum limit.