Short-wave excitations in non-local Gross-Pitaevskii model
Abstract
We show that a non-local form of the Gross-Pitaevskii equation describes not only long-wave excitations, but also the short-wave ones in Bose-condensate systems. At certain parameter values, the excitation spectrum mimics the Landau spectrum of quasi-particle excitations in superfluid helium with roton minimum. The excitation wavelength, at which the roton minimum exists, is close to the inter-particle interaction range. We determine how the roton gap and the effective roton mass depend on the interaction potential parameters, and show that the existence domain of the spectrum with a roton minimum is reduced if one accounts for an inter-particle attraction.
- Publication:
-
Central European Journal of Physics
- Pub Date:
- June 2011
- DOI:
- 10.2478/s11534-010-0124-7
- arXiv:
- arXiv:1004.0442
- Bibcode:
- 2011CEJPh...9..857I
- Keywords:
-
- quasi-particle excitations;
- Gross-Pitaevskii equation;
- Landau spectrum;
- roton minimum;
- quasi-particle excitations;
- Gross-Pitaevskii equation;
- Landau spectrum;
- roton minimum;
- Condensed Matter - Statistical Mechanics
- E-Print:
- 5 pages, 5 figures, UJP style