Towards quantum transport for central collisions of nuclei and of clouds of ultracold quantum gases*

Efforts are on the way to develop a practical non-equilibrium Green's functions approach to central nuclear reactions. A truncation of the far off-diagonal elements of the spatial density matrix is implemented, resulting in speedup without affecting the evolution of the system close to the diagonal. The technique is applied to a simulation of collisions between quasi-1D Bose-Einstein condensates, using a modified Gross-Pitaevskii equation that allows inclusion of some transverse degrees of freedom in a one dimensional environment.