  We study the dynamical generation of the chiral chemical potential in a Weyl
metal constructed from a three-dimensional optical lattice and subject to
synthetic gauge fields. By numerically solving the Boltzmann equation with the
Berry curvature in the presence of parallel synthetic electric and magnetic
fields, we find that the spectral flow and the ensuing chiral magnetic current
emerge. We show that the spectral flow and the chiral chemical potential can be
probed by time-of-flight imaging.
