The inverse-square interaction phase diagram: unitarity in the bosonic ground state
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hdl:2117/119209
Tipus de documentArticle
Data publicació2018-06-08
EditorMultidisciplinary Digital Publishing Institute (MDPI)
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Abstract
Ground-state properties of bosons interacting via inverse square potential (three dimensional Calogero-Sutherland model) are analyzed. A number of quantities scale with the density and can be naturally expressed in units of the Fermi energy and Fermi momentum multiplied by a dimensionless constant (Bertsch parameter). Two analytical approaches are developed: the Bogoliubov theory for weak and the harmonic approximation (HA) for strong interactions. Diffusion Monte Carlo method is used to obtain the ground-state properties in a non-perturbative manner. We report the dependence of the Bertsch parameter on the interaction strength and construct a Padé approximant which fits the numerical data and reproduces correctly the asymptotic limits of weak and strong interactions. We find good agreement with beyond-mean field theory for the energy and the condensate fraction. The pair distribution function and the static structure factor are reported for a number of characteristic interactions. We demonstrate that the system experiences a gas-solid phase transition as a function of the dimensionless interaction strength. A peculiarity of the system is that by changing the density it is not possible to induce the phase transition. We show that the low-lying excitation spectrum contains plasmons in both phases, in agreement with the Bogoliubov and HA theories. Finally, we argue that this model can be interpreted as a realization of the unitary limit of a Bose system with the advantage that the system stays in the genuine ground state contrarily to the metastable state realized in experiments with short-range Bose gases.
CitacióAstrakharchik, G., Kryuchkov, P. S., Kurbakov, I. L., Lozovik, Y. The inverse-square interaction phase diagram: unitarity in the bosonic ground state. "Crystals", 8 Juny 2018, vol. 8, núm. 6, p. 246-1-246-26.
ISSN2073-4352
Versió de l'editorhttp://www.mdpi.com/2073-4352/8/6/246
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