Moment of Inertia and Superfluidity of a Trapped Bose Gas

The temperature dependence of the moment of inertia of a dilute Bose gas confined in a harmonic trap is determined. Deviations from the rigid value, due to the occurrence of Bose-Einstein condensation, reveal the superfluid behavior of the system. In the noninteracting gas these deviations become important at temperatures of the order of $T_c{N}^{-1\mathrm{}/12}$. The role of interactions is also discussed.