Davide Galli — Universit&agrave di Milano #
<i>Ab initio</i> study of Kelvin waves in superfluid 4He #
We have performed a microscopic study of a quantized vortex line in condensed 4He at zero temperature using the shadow 
path integral ground state method and the fixed phase approximation [Phys. Rev. B 89, 224516 (2014)].
The inclusion of backflow correlations in the phase improves the description of the vortex with respect to the 
Onsager-Feynman phase by a large reduction of the core energy of the topological excitation. A vortex line has 
excited states in the form of Kelvin waves in which the vortex is no longer straight but its core moves in a helical way. The phase with backflow induces a partial filling of the vortex core; we interpret the delocalization of vorticity achieved with the backflow phase as due to the zero point motion of Kelvin waves. This opens the possibility to investigate microscopically Kelvin waves via analytic continuation of suitable imaginary time correlation functions 
computed via Quantum Monte Carlo simulations. Preliminary results will be shown.