Nonlinear Bose-Einstein-condensate Dynamics Induced by a Harmonic Modulation of the s-wave Scattering Length

TL;DR

This paper investigates the nonlinear dynamics of a Bose-Einstein condensate under harmonic modulation of the scattering length, revealing mode coupling, harmonic generation, and frequency shifts through analytical and numerical methods.

Contribution

It combines analytical perturbation theory with numerical simulations to analyze nonlinear BEC dynamics induced by scattering length modulation at zero temperature.

Findings

Identification of mode coupling and higher harmonic generation

Observation of significant frequency shifts in collective modes

Proposals for experimental observation of nonlinear effects

Abstract

In a recent experiment, a Bose-Einstein condensate of Li7 has been excited by a harmonic modulation of the atomic s-wave scattering length via Feshbach resonance. By combining an analytical perturbative approach with extensive numerical simulations we analyze the emerging nonlinear dynamics of the system on the mean-field Gross-Pitaevskii level at zero temperature. Resulting excitation spectra are presented and prominent nonlinear features are found: mode coupling, higher harmonics generation and significant shifts in the frequencies of collective modes. We indicate how nonlinear dynamical properties could be made clearly observable in future experiments and compared to our results.