Matter-wave collimation to picokelvin energies with scattering length and potential shape control

TL;DR

This paper demonstrates matter-wave collimation of a Bose-Einstein condensate to picokelvin energies by controlling scattering length and potential shape, enhancing atom interferometry without microgravity.

Contribution

It introduces a novel lensing protocol to tailor atomic interactions, achieving record low energies and proposing a method for even lower 3D energies with additional pulsed techniques.

Findings

Achieved 340 pK energy in one dimension through interaction tailoring.

Supported by simulations, extrapolated 2D expansion energy of 438 pK.

Proposed a method to reach below 16 pK in 3D energies with pulsed delta-kick.

Abstract

The sensitivity of atom interferometers depends on their ability to realize long pulse separation times and prevent loss of contrast by limiting the expansion of the atomic ensemble within the interferometer beam through matter-wave collimation. Here we investigate the impact of atomic interactions on collimation by applying a lensing protocol to a $^{39}$K Bose-Einstein condensate at different scattering lengths. Tailoring interactions, we measure energies corresponding to $340 \pm 12$ pK in one direction. Our results are supported by an accurate simulation, which allows us to extrapolate a 2D ballistic expansion energy of $438 \pm 77$ pK. Based on our findings we propose an advanced scenario, which enables 3D expansion energies below $16$ pK by implementing an additional pulsed delta-kick. Our results pave the way to realize ensembles with more than $1\times10^5$ atoms and 3D energies in the two-digit pK range in typical dipole trap setups without the need for micro-gravity or long baseline environments.