Anisotropic scattering of Bogoliubov excitations
Abstract
We consider elementary excitations of an interacting Bose-Einstein condensate in the mean-field framework. As a building block for understanding the dynamics of systems comprising interaction and disorder, we study the scattering of Bogoliubov excitations by a single external impurity potential. A numerical integration of the Gross-Pitaevskii equation shows that the single-scattering amplitude has a marked angular anisotropy. By a saddle point expansion of the hydrodynamic mean-field energy functional, we derive the relevant scattering amplitude including the crossover from sound-like to particle-like excitations. The very different scattering properties of these limiting cases are smoothly connected by an angular envelope function with a well-defined node of vanishing scattering amplitude. We find that the overall scattering is most efficient at the crossover from phonon-like to particle-like Bogoliubov excitations.
- Publication:
-
EPL (Europhysics Letters)
- Pub Date:
- July 2008
- DOI:
- 10.1209/0295-5075/83/10006
- arXiv:
- arXiv:0802.4366
- Bibcode:
- 2008EL.....8310006G
- Keywords:
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- Condensed Matter - Other
- E-Print:
- 5 pages, 5 figures