Excited states inHe4described by a shadow wave function

Abstract

The idea of the shadow wave function, which incorporates quantum delocalization of particles in the description of quantum liquids and solids, is applied to excited states of liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. With a simple Feynman shadow wave function we compute the phonon-roton excitation spectrum by a Monte Carlo method at three different densities. The variation of the excitation energy with density is consistent with the behavior of the experimental data. The energy near the roton minimum is in excellent agreement with experiment at all densities.