Massive Charged Strings in the Description of Vortex Ring Quantum Nucleation

We demonstrate the way in which vortex rings in neutral superfluids are equivalent to massive, charged, elastic strings in an electromagnetic field defined locally on the string from a Kalb-Ramond gauge field. We argue that the action thus obtained describes an intermediate scale of vortex motion with phonon fluctuations of the line between the incompressible hydrodynamic r\'egime and the microscopic one dominated by roton emission and absorption. The formalism gives an accurate semiclassical picture of vortex string motion and is of relevance for the description of vortex ring quantum nucleation in a perturbation theory of the purely incompressible case.