Dislocation-vibration model for nonclassical rotational inertia

A dislocation model for the nonclassical rotational inertia is proposed. Temperature dependence of the period of the torsional oscillator containing solid helium is derived from the variation in the average pinning length of dislocations in solid helium. The mechanism is that the vibration of dislocations causes the wave number of the shear wave in solid helium to increase. Consequently the apparent moment of inertia of solid helium is increased with increasing temperature.