Collective excitations of a dipolar Bose-Einstein condensate

TL;DR

This study investigates how dipole-dipole interactions influence collective excitation frequencies in a Bose-Einstein condensate, confirming theoretical predictions and highlighting the importance of trap geometry and atom number.

Contribution

The paper provides experimental validation of dipolar effects on collective modes and compares results with theoretical and simulation models, emphasizing the role of trap geometry.

Findings

Dipolar interactions cause measurable shifts in collective mode frequencies.

Experimental results align with zero temperature theoretical predictions.

Dipolar effects depend significantly on trap geometry and atom number.

Abstract

We have measured the effect of dipole-dipole interactions on the frequency of a collective mode of a Bose-Einstein condensate. At relatively large numbers of atoms, the experimental measurements are in good agreement with zero temperature theoretical predictions based on the Thomas Fermi approach. Experimental results obtained for the dipolar shift of a collective mode show a larger dependency to both the trap geometry and the atom number than the ones obtained when measuring the modification of the condensate aspect ratio due to dipolar forces. These findings are in good agreement with simulations based on a gaussian ansatz.