  We study the dynamical response of a Tonks-Girardeau gas on a ring induced by
a moving delta-barrier potential. An exact solution based on the time-dependent
Bose-Fermi mapping allows to obtain the particle current, its fluctuations and
the drag force acting on the barrier. The exact solution is analyzed
numerically as well as analytically in the perturbative regime of weak barrier
strength. In the weak barrier limit the stirring drives the system into a state
with net zero current for velocities $v$ smaller than $v_c=\pi\hbar /mL$, with
$m$ the atomic mass and $L$ the ring circumference. At $v$ approaching $v_c$
angular momentum can be transferred to the fluid and a nonzero drag force
arises. The existence of a velocity threshold for current generation indicates
superfluid-like behavior of the mesoscopic Tonks-Girardeau gas, different from
the non-superfluid behavior predicted for Tonks-Girardeau gas in an infinite
tube.
