(color online) (a) Time evolutions of currents for finite uniform fermionic systems. for all systems. (b) Time evolutions of currents for systems with different ways of changing to . Corresponding are shown in the inset. Systems are with L = 500 and 200 fermions. (c) Time evolutions of currents for systems with a few particles. Systems are with L = 500 and . (d) The amplitude of QSSC versus the phase difference for fermionic systems with different filling factors. Inset in panel (d): versus the filling factor β for fermionic systems with L = 500 and .