Computational methods for laser-atom interactions

We discuss a computational method to study the dynamics in the laser-atom interactions. There are two key ingredients to the new method. Firstly, we transform the differential time-dependent Schroedinger equation into a time-integral equation, in which the dynamics related wavefunction is separated from the background wavefunction analytically to improve the numerical accuracy. Secondly, we divide the space into an inner region and an outer region, and propagate the inner-region wavefunction in the full Hamiltonian numerically and outer-region wavefunction in the momentum space analytically. In this way, we remove the physical boundary in space. To show the effectiveness of the method, we simulate the carrier-envelop phase dependent high energy above-threshold-ionization yields, which are in good agreement with the experimental observations. Furthermore, we investigate the rescattering electron momentum spectra and provide an intuitive rescattering picture from a full quantum non-perturbative calculation