Darmstadt 2008 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 40: Quantengase (Bosonen I)

Q 40.2: Talk

Thursday, March 13, 2008, 14:15–14:30, 1A

Anisotropic scattering of Bogoliubov quasi particles — •Christopher Gaul and Cord A. Müller — Universität Bayreuth

In order to study the interplay of disorder and interaction in atomic BECs, we investigate scattering of Bogoliubov quasi particles (BQP) by the spatial fluctuations of an external optical potential. We first calculate the amplitude for a single scattering event. In contrast to the case of noninteracting particles, the scattering amplitude of BQPs has a sign change and consequently a node at a certain angle. In the long-wavelength limit, we understand this as a fundamental sound-wave property, which becomes apparent in a hydrodynamic formulation. This scattering anisotropy has the curious consequence that in the 2D multiple-scattering regime the diffusive Boltzmann transport length becomes shorter than the scattering mean free path for particle-like excitations scattered by short-range correlated potentials.