Expansion dynamics of Fermi atoms in optical lattice

• We use DBdG method and TEBD to investigate the expansion dynamics in optical lattice.
• We calculate the evolution of density and superfluid order parameters.
• We find a ballistic expansion result for non-interacting case.
• We find interaction damps the expansion rate exponentially.

We study the non-equilibrium quantum dynamics of attractive Fermi gases in one- and two-dimensional optical lattice. We use the dynamic Bogoliubov–de Gennes (DBdG) method and time-evolving block decimation (TEBD) to investigate the expansion dynamics, which can be implemented by suddenly removing the harmonic trap. The evolutions of density and superfluid order parameters have been calculated. We find that for the noninteracting case, the expansion rate is linear with hopping amplitude, which is a ballistic expansion result. And the interaction damps the expansion rate exponentially both in one and two dimensions and makes it deviate from the ballistic expansion.