Quantum Scattering in an Optical Collider for Ultracold Atoms

TL;DR

This paper presents an experimental study of ultracold atom collisions using an optical collider, enabling detailed exploration of scattering resonances and partial wave phenomena at energies much higher than thermal levels.

Contribution

It introduces a versatile all-optical atom collider capable of probing various scattering resonances and partial waves in ultracold atoms, including heteronuclear and fermionic systems.

Findings

Observation of p-wave scattering with fermions

Detection of inelastic scattering near Feshbach resonances

Identification of partial wave interference effects

Abstract

We report on experiments investigating the collisional properties of atoms at ultralow collision energies using an all-optical atom collider. By using a pair of optical tweezers, we can manipulate two ultracold atom clouds and collide them together at energies up to three orders of magnitude larger than their thermal energy. Our experiments measure the scattering of $\rm ^{87}Rb$, $\rm ^{40}K$, and $\rm ^{40}K$-$\rm ^{87}Rb$ collisions. The versatility of our collider allows us to probe both shape resonances and Feshbach resonances in any partial wave. As examples, we present experiments demonstrating p-wave scattering with indistinguishable fermions, inelastic scattering at non-zero energies near a homonuclear Feshbach resonance, and partial wave interference in heteronuclear collisions.