Nonlinear resonances in \delta-kicked Bose-Einstein Condensates

TL;DR

This paper explores the nonlinear dynamics of a periodically kicked Bose-Einstein condensate in the quantum resonance regime, revealing abrupt cut-offs and instabilities linked to Beliaev and Landau processes.

Contribution

It uncovers the role of nonlinear interactions causing cut-offs and instabilities in quantum resonances of kicked BECs, highlighting new excitation pathways.

Findings

Abrupt cut-off at main Talbot time QR

Nonlinear excitation involving Beliaev and Landau processes

Exponential oscillations indicating dynamical instability

Abstract

We investigate the Quantum Resonance (QR) regime of a periodically kicked atomic Bose-Einstein condensate. We find that the clearest indicator of the nonlinear dynamics is a surprisingly abrupt cut-off which appears on the main "Talbot time" QR. We show that this is due and excitation path combining both Beliaev and Landau processes, with some analogies to nonlinear self-trapping. Investigation of dynamical instability reveals further symptoms of nonlinearity such as a regime of exponential oscillations.