Microscopic calculation of the phonon-roton branch in superfluid $^4$He

J. Boronat; J. Casulleras

doi:10.1209/epl/i1997-00240-x

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Microscopic calculation of the phonon-roton branch in superfluid $^4$He

J. Boronat·J. Casulleras

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Abstract

Diffusion Monte Carlo results for the phonon-roton excitation branch in bulk liquid $^4$He at zero temperature are presented. The sign problem associated to the excited wave function has been dealt both with the fixed-node approximation and the released-node technique. The upper bounds provided by the fixed-node approximation are shown to become exact when using the released-node method. An excellent agreement with experimental data is achieved both at the equilibrium and near the freezing densities.

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J. Boronat, J. Casulleras. 1996-07-29. Microscopic calculation of the phonon-roton branch in superfluid $^4$He. https://doi.org/10.1209/epl%2Fi1997-00240-x

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