Absorbing boundary conditions for the finite-difference time-domain calculation of the one-dimensional Schrödinger equation

The absorbing boundary conditions for the finite-difference calculation of the time-dependent one-dimensional Schr\"odinger equation are presented. These are the local boundary conditions that approximate the one-way wave equation of a wave function. The conditions minimize undesirable reflections at the artificial boundaries of the area of computation, thus enabling us to limit the computation area efficiently. The calculations of the transmission coefficient of multibarrier tunneling show the validity of the method.