We obtain ab-initio estimations of the dynamic structure factor, S(q,ω), of Bose gases at zero temperature. More precisely, we use the Genetic Inversion via Falsification of Theories (GIFT) algorithm to perform analytic continuations of imaginary time correlation functions computed via an exact Path Integral projector method. Using the hard-sphere potential to model the two-body interactions between the atoms, we compute S(q,ω) changing the gas parameter from the dilute regime (na3 10-4) up to the density corresponding to superfluid 4He at equilibrium (na 3 0.2138). With increasing density, we observe the emergence of a broad multiphonon contribution accompanying the quasiparticle peak and a crossover of the dispersion of elementary excitations from a Bogoliubov-like spectrum to a phonon-maxon- roton curve. Apart from the low wave vector region, for na3 0.2138 the energy-momentum dispersion relation and the static density response function, χ(q), turns out to be in good agreement with the superfluid 4He experimental data at equilibrium density.

Many-body Bose systems and the hard-sphere model : dynamic properties from the weak to the strong interaction regime / R. Rota, F. Tramonto, D.E. Galli, S. Giorgini. - In: JOURNAL OF PHYSICS. CONFERENCE SERIES. - ISSN 1742-6588. - 529:1(2014), pp. 012022.1-012022.10. ((Intervento presentato al 17. convegno International conference on recent progress in many-body theories, MBT tenutosi a Rostock (Germany) nel 2013.

Many-body Bose systems and the hard-sphere model : dynamic properties from the weak to the strong interaction regime

F. Tramonto
Secondo
;
D.E. Galli
Penultimo
;
2014

Abstract

We obtain ab-initio estimations of the dynamic structure factor, S(q,ω), of Bose gases at zero temperature. More precisely, we use the Genetic Inversion via Falsification of Theories (GIFT) algorithm to perform analytic continuations of imaginary time correlation functions computed via an exact Path Integral projector method. Using the hard-sphere potential to model the two-body interactions between the atoms, we compute S(q,ω) changing the gas parameter from the dilute regime (na3 10-4) up to the density corresponding to superfluid 4He at equilibrium (na 3 0.2138). With increasing density, we observe the emergence of a broad multiphonon contribution accompanying the quasiparticle peak and a crossover of the dispersion of elementary excitations from a Bogoliubov-like spectrum to a phonon-maxon- roton curve. Apart from the low wave vector region, for na3 0.2138 the energy-momentum dispersion relation and the static density response function, χ(q), turns out to be in good agreement with the superfluid 4He experimental data at equilibrium density.
Settore FIS/03 - Fisica della Materia
Deutsche Forschungsgemeinschaft
Institute of Physics
Sonderforschungsbereich 652
University of Rostock
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/255881
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 3
  • ???jsp.display-item.citation.isi??? 3
social impact