  We consider a two-component Fermi gas in the presence of spin imbalance,
modeling the system in terms of a one-dimensional attractive Hubbard
Hamiltonian initially in the presence of a confining trap potential. With the
aid of the time-evolving block decimation method, we investigate the dynamics
of the initial state when the trap is switched off. We show that the dynamics
of a gas initially in the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state is
decomposed into the independent expansion of two fluids, namely the paired and
the unpaired particles. In particular, the expansion velocity of the unpaired
cloud is shown to be directly related to the FFLO momentum. This provides an
unambiguous signature of the FFLO state in a remarkably simple way.
