A fourth-order compact time-splitting method for the Dirac equation with time-dependent potentials

In this paper, we present an approach to deal with the dynamics of Dirac equation time-dependent electromagnetic potentials using fourth-order compact time-splitting method ($S_\text{4c}$). To purpose, time-ordering technique for Hamiltonians is introduced, so that influence time-dependence could be limited certain steps which are easy treat. Actually, in case equation, it turns out only those involving need amended, and scheme remains efficient, accurate, as well implement. Numerical examples 1D 2D given validate scheme.