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arXiv · 0802.4366

Anisotropic scattering of Bogoliubov excitations

Christopher Gaul·Cord Axel Müller
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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.

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Christopher Gaul, Cord Axel Müller. 2008-06-18. Anisotropic scattering of Bogoliubov excitations. https://doi.org/10.1209/0295-5075/83/10006

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