MANY-BODY STRUCTURE OF QUANTUM VORTICES IN THIN HE-4 FILMS

We propose a microscopic theory of quantum vortices in two-dimensional He-4, applicable to thin superfluid He-4 films. The theory describes the vortex core and reproduces the classical logarithmic behavior at large distances. The single vortex is treated as a quasiparticle. We calculate the energy needed to create a single vortex, the vortex inertial mass, the microscopic interaction between vortices and the binding energy of the vortex-antivortex pair as a function of density at zero temperature. At He-4 densities less than 0.037 Angstrom(-2) the binding energy of the vortex-antivortex pair becomes negative, indicating an instability for the creation of a novel state.