VORTEX LINE IN SUPERFLUID HE-4 - A VARIATIONAL MONTE-CARLO CALCULATION

We present a Monte Carlo investigation of a vortex line in superfluid He-4 in a cylindrical container. We compute the excitation energy and the density profile for two different trial functions. The first is th e standard Onsager-Feynman form for an excited vortex state. This give s a singular velocity on the axis of the vortex and a hollow core. In our second approach, a shadow wave function, is used to model the vort ex state through the auxiliary, or shadow variables. As a consequence, the vorticity is distributed over a finite region and the density doe s not vanish at the vortex axis. This second wave function gives a sub stantially lower energy than the wave function of the Onsager-Feynman form.