“…There have been extensive theoretical studies on the KGD (1.1) system, including the local and global well-posedness of the Cauchy problem and the existences of bound state solutions, for which we refer to [2,14,15,19,20,23,24,32,35] and references therein. For the numerical part, different kinds of numerical methods, including the finite difference time domain (FDTD) methods and spectral methods have been proposed and analyzed for efficient computations of wave propagation in classical quantum physics, i.e., dispersive waves in the Gross-Pitaevskii equation [3], the Klein-Gordon equation [7,8,12,22,29,34,40,43], the Dirac equation [1, 4-6, 26, 28, 30, 39], the Klein-Gordon-Schrodinger equations [10,21], the Klein-Gordon-Zakharov equations [11,16,37], the Maxwell-Dirac equations [9,31], etc. However, the approaches for KGD (1.1) proposed in the literature [17,41,42] are limited.…”