Observation of quantization of circulation in rotating superfluidHe4

Abstract

New measurements of the superfluid circulation in rotating liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ by the vibrating-wire method show quantum steps. With the exception of the results for one wire, the observed quantum of circulation equals $\frac{h}{m_4}$ as expected from theory, where $h$ is Planck's constant and $m_4$ is the mass of a ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ atom. The wires had diameters from 15 to 35 μm, the temperatures lay in the interval $0.3<T<\mathrm{}0.7\mathrm{}$ K, the rotation speeds ranged from 0 to 4 rad/s, and quantum levels of circulation were observed with magnitudes from 1 to 4 times $\frac{h}{m_4}$.