A change in the phase of the order parameter of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$A$ can be undone by a subsequent rotation. We investigate the dynamical consequence of this broken relative gauge and rotational symmetry. In particular a wheel rotated in the liquid acts as a "gauge transformer" driving a superflow. Such experiments provide a very direct probe of this unusual feature of the order parameter, at the same time measuring the orbital quantum number of the pairs.

• Received 28 September 1978

DOI:https://doi.org/10.1103/PhysRevLett.43.296