Quantum Scattering in an Optical Collider for Ultracold Atoms

Abstract

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 87 Rb, 40 K, and 40 K-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.

Effects of quantum mechanical identity in particle scattering: experimental observations (and lack thereof)

“…I should note that partial wave interference is not an effect due to the particles being identical. Indeed, Thomas et al (2017) presents a case of s+p partial-wave interference for colliding rubidium and potassium atoms. As such, partial-wave interference is brought about by two 'pathways's and pfor a single atom, akin to Young's double slit experiment.…”

Bosonic Quantum Dynamics Following Colliding Potential Wells

“…These advancements sparked strong interest to use optical tweezers for the precise manipulation of ensembles of ultracold neutral atoms [38] including Rydberg atoms [39][40][41]. A very interesting direction of research is to use multiple optical tweezers to accelerate atomic clouds [42] which allows to set up optical colliders [43][44][45]. In these experiments, fundamental properties of quantum scattering processes were observed such as partial wave interference or the loss of particles on resonant collisions.…”

Counterflow dynamics of two correlated impurities immersed in a bosonic gas

“…For a single atomic species these protocols result in the oscillation of the formed dark solitons [42] or in the case of a two-component mixture in the spontaneous generation of dark-bright soliton trains [41]. Another technique to initiate atomic collisions constitutes of two counter-propagating harmonic oscillator potentials [43] which has been experimentally realized with 40 K and 87 Rb clouds utilizing two optical tweezers [44,45].…”