Pair Correlations and Photoassociation Dynamics of Two Atoms in an Optical Tweezer.

We investigate the photoassociation dynamics of exactly two laser-cooled ^{85}Rb atoms in an optical tweezer and reveal fundamentally different behavior to photoassociation in many-atom ensembles. We observe nonexponential decay in our two-atom experiment that cannot be described by a single rate coefficient and find its origin in our system's pair correlation. This is in stark contrast to many-atom photoassociation dynamics, which are governed by decay with a single rate coefficient. We also investigate photoassociation in a three-atom system, thereby probing the transition from two-atom dynamics to many-atom dynamics. Our experiments reveal additional reaction dynamics that are only accessible through the control of single atoms and suggest photoassociation could measure pair correlations in few-atom systems. It further showcases our complete control over the quantum state of individual atoms and molecules, which provides information unobtainable from many-atom experiments.

An atomic Fabry-Perot interferometer using a pulsed interacting Bose-Einstein condensate.

We numerically demonstrate atomic Fabry-Perot resonances for a pulsed interacting Bose-Einstein condensate (BEC) source transmitting through double Gaussian barriers. These resonances are observable for an experimentally-feasible parameter choice, which we determined using a previously-developed analytical model for a plane matter-wave incident on a double rectangular barrier system. Through numerical simulations using the non-polynomial Schödinger equation-an effective one-dimensional Gross-Pitaevskii equation-we investigate the effect of atom number, scattering length, and BEC momentum width on the resonant transmission peaks. For [Formula: see text]Rb atomic sources with the current experimentally-achievable momentum width of [Formula: see text] [[Formula: see text]], we show that reasonably high contrast Fabry-Perot resonant transmission peaks can be observed using (a) non-interacting BECs, (b) interacting BECs of [Formula: see text] atoms with s-wave scattering lengths [Formula: see text] ([Formula: see text] is the Bohr radius), and (c) interacting BECs of [Formula: see text] atoms with [Formula: see text]. Our theoretical investigation impacts any future experimental realization of an atomic Fabry-Perot interferometer with an ultracold atomic source.