Numerical study of chiral symmetry breaking in non-Abelian gauge theory with background magnetic field

P. V. Buividovich, M. N. Chernodub, E. V. Luschevskaya, M. I. Polikarpov

Published 2008-12-09, updated 2009-11-09Version 2

We investigate the effect of a uniform background magnetic field on the chiral symmetry breaking in SU(2) Yang-Mills theory on the lattice. We observe that the chiral condensate grows linearly with the field strength B up to \sqrt{e B} = 3 GeV as predicted by chiral perturbation theory for full QCD. As the temperature increases the coefficient in front of the linear term gets smaller. In the magnetic field near-zero eigenmodes of the Dirac operator tend to have more regular structure with larger (compared to zero-field case) Hausdorff dimensionality. We suggest that the delocalization of near-zero eigenmodes plays a crucial role in the enhancement of the chiral symmetry breaking.