Density waves and jet emission asymmetry in Bose Fireworks

TL;DR

This study combines experiments and simulations to show that density waves in a driven Bose condensate serve as a precursor to matter-wave jet emission, explaining pattern formation and asymmetry.

Contribution

It identifies a density wave stage that precedes jet emission and links it to the pattern and asymmetry observed in Bose fireworks.

Findings

Density waves form before jet emission.

Density waves determine jet pattern and asymmetry.

Jet emission is consistent with momentum conservation.

Abstract

A Bose condensate subject to a periodic modulation of the two-body interactions was recently observed to emit matter-wave jets resembling "fireworks" [Nature 551, 356(2017)]. In this paper, combining experiment with numerical simulation, we demonstrate that these "Bose fireworks" represent a late stage in a complex time evolution of the driven condensate. We identify a "density wave" stage which precedes jet emission and results from interference of matterwaves. The density waves self-organize and self-amplify without the breaking of long range translational symmetry. Importantly, this density wave structure deterministically establishes the template for the subsequent patterns of the emitted jets. Our simulations, in good agreement with experiment, also address the apparent asymmetry in the jet pattern and show it is fully consistent with momentum conservation.