Quantum reflection of bright solitary matter-waves from a narrow attractive potential

TL;DR

This study demonstrates quantum reflection of bright solitary matter-waves from a narrow attractive potential, revealing higher-than-expected reflection rates likely caused by small intensity maxima in the laser beam.

Contribution

It provides the first experimental observation of quantum reflection of bright solitons from narrow attractive potentials and explains the enhanced reflection through detailed modeling.

Findings

Up to 25% atomic reflection observed.

Reflection exceeds theoretical predictions for ideal Gaussian potentials.

Small intensity maxima in the laser beam enhance reflection.

Abstract

We report the observation of quantum reflection from a narrow, attractive, potential using bright solitary matter-waves formed from a 85Rb Bose-Einstein condensate. We create narrow potentials using a tightly focused, red-detuned laser beam, and observe reflection of up to 25% of the atoms, along with the trapping of atoms at the position of the beam. We show that the observed reflected fraction is much larger than theoretical predictions for a narrow Gaussian potential well; a more detailed model of bright soliton propagation, accounting for the generic presence of small subsidiary intensity maxima in the red-detuned beam, suggests that these small intensity maxima are the cause of this enhanced reflection.