Anisotropic excitation spectrum of a dipolar quantum Bose gas

Abstract

We measure the excitation spectrum of a dipolar Chromium Bose Einstein Condensate with Raman-Bragg spectroscopy. The energy spectrum depends on the orientation of the dipoles with respect to the excitation momentum, demonstrating an anisotropy which originates from the dipole-dipole interactions between the atoms. We compare our results with the Bogoliubov theory based on the local density approximation, and, at large excitation wavelengths, with numerical simulations of the time dependent Gross-Pitaevskii equation. Our results show an anisotropy of the speed of sound

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References in corpus (8)

• Bose-Einstein condensation of chromium
• Bose-Einstein Condensation of Erbium
• Observation of dipole-dipole interaction in a degenerate quantum gas
• Quantum degenerate dipolar Fermi gas
• d-wave collapse and explosion of a dipolar Bose-Einstein condensate
• Roton-type mode softening in a quantum gas with cavity-mediated long-range interactions
• All-Optical Production of Chromium Bose-Einstein Condensates
• Collective oscillations of dipolar Bose-Einstein condensates and accurate comparison between contact and dipolar interaction

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