NMR Experiments on Rotating SuperfluidHe3-A: Evidence for Vorticity

Experiments on rotating superfluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A$ in an open cylindrical geometry show a change in the NMR line shape as a result of rotation: The amplitude of the peak decreases in proportion to $f\left(T\right)g\left(\Omega \right)$, where $\Omega$ is the angular velocity of rotation; at the same time the line broadens. Near $T_c$, $f\left(T\right)\mathrm{}$ is a linear function of $1-\frac{T}{T_c}$. At small velocities $g\left(\Omega \right)\propto \Omega$. These observations are consistent with the existence of vortices in rotating ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A$.