Chiral Properties of Strong Interactions in a Magnetic Background

TL;DR

This study uses lattice QCD simulations to analyze how strong magnetic fields influence chiral symmetry breaking in low-temperature QCD, revealing the significant role of gauge field modifications in magnetic catalysis.

Contribution

First lattice QCD investigation of magnetic catalysis effects on chiral properties with detailed analysis of gauge field contributions.

Findings

Chiral condensate increases with magnetic field strength.

Gauge field modifications significantly contribute to magnetic catalysis.

Results align with some model predictions but highlight the importance of dynamical quark effects.

Abstract

We investigate the chiral properties of QCD in presence of a magnetic background field and in the low temperature regime, by lattice numerical simulations of N_f = 2 QCD. We adopt a standard staggered discretization, with a pion mass around 200 MeV, and explore a range of magnetic fields (180 MeV)^2 \leq|e|B \leq (700 MeV)^2, in which we study magnetic catalysis, i.e. the increase of chiral symmetry breaking induced by the background field. We determine the dependence of the chiral condensate on the external field, compare our results with existing model predictions and show that a substantial contribution to magnetic catalysis comes from the modified distribution of non-Abelian gauge fields, induced by the magnetic field via dynamical quark loop effects.