  We studied the Berry curvature of the massive Dirac fermion in 3+1
dimensions. For the non-interacting Dirac fermion, the Berry curvature is
non-Abelian because of the degeneracy of positive and negative helicity modes.
We calculated the non-Abelian Berry curvature analytically and numerically. For
the interacting Dirac fermion in QCD, the degeneracy is lost because gluons
carry helicity and color charge. We calculated the Abelian Berry curvature in
lattice QCD.
