Collective excitation of a Bose-Einstein condensate by modulation of the atomic scattering length

TL;DR

This paper demonstrates the excitation of quadrupole modes in a Bose-Einstein condensate by modulating atomic interactions, revealing resonance behaviors and validating results with numerical simulations.

Contribution

It introduces a method to excite collective modes in BECs through scattering length modulation and provides experimental and theoretical analysis of the resonances.

Findings

Resonances at natural quadrupole frequency and first harmonic observed.

Excitation amplitude depends on modulation depth.

Numerical simulations agree with experimental results.

Abstract

We excite the lowest-lying quadrupole mode of a Bose-Einstein condensate by modulating the atomic scattering length via a Feshbach resonance. Excitation occurs at various modulation frequencies, and resonances located at the natural quadrupole frequency of the condensate and at the first harmonic are observed. We also investigate the amplitude of the excited mode as a function of modulation depth. Numerical simulations based on a variational calculation agree with our experimental results and provide insight into the observed behavior.