Quantum Monte Carlo study of the dynamic structure factor in the gas and crystal phase of hard-sphere bosons

Abstract

We investigate the dynamic structure factor of a system of Bose particles at zero temperature using quantum Monte Carlo methods. Interactions are modeled using a hard-sphere potential of size $a$ and simulations are performed for values of the gas parameter $n{a}^3$ ranging from the dilute regime up to densities $n$ where the thermodynamically stable phase is a solid. With increasing density we observe a crossover of the dispersion of elementary excitations from a Bogoliubov-like spectrum to a phonon--maxon--roton curve and the emergence of a broad multiphonon contribution accompanying the single-quasiparticle peak. In particular, for $n{a}^3=0.2138$, which corresponds to superfluid ${}^4$He at equilibrium density, the extracted spectrum turns out to be in good agreement with the experimental energy--momentum dispersion relation in the roton region and for higher momenta. The behavior of the spectral function at the same density in the stable solid and metastable gas phase above the freezing point is also discussed.

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Cited by in corpus (14)

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• One-dimensional liquid ${}^4$He: dynamical properties beyond Luttinger liquid theory
• Quasiparticle energy in a strongly interacting homogeneous Bose-Einstein condensate
• Statistical and computational intelligence approach to analytic continuation in Quantum Monte Carlo
• Path integral Monte Carlo ground state approach: Formalism, implementation, and applications
• Dynamical structure factor of one-dimensional hard rods
• Quantum Monte Carlo study of a vortex in superfluid ${}^4$He and search for a vortex state in the solid
• Microscopic study of static and dynamical properties of dilute one-dimensional soft bosons
• Roton excitations and the fluid-solid phase transition in superfluid 2D Yukawa Bosons
• Roton in a few-body dipolar system
• Linear response of one-dimensional liquid ${}^4$He to external perturbations
• Hole-induced anomaly in the thermodynamic behavior of a one-dimensional Bose gas
• Stochastic method for calculating the ground state reduced density matrix of trapped Bose particles in one dimension