Expansion after a geometric quench of an atomic polarized attractive Fermi gas in one dimension

The expansion of an ultracold lattice gas of fermions in a one-dimensional optical lattice after a geometric quench in which the atoms are released from a box (or parabolic) trap is studied numerically using the time-dependent density matrix renormalization group method. It is found that the momentum distributions of the two atomic species present in the simulations quickly converge toward stationary values dictated by the integrals of motion of the lattice gas at the expansion onset. An account of the central results and some of the technical details is given along with explicit examples.