En ligne depuis Hanovre :
https://universite-paris-saclay-fr.zoom.us/j/92780507800?pwd=LYWppq1poO0KYkaXTENwbMM1d6aGbp.1
Matter-Wave Lensing of Dual-Species Bose-Einstein Condensates in the Picokelvin Regime for Ground and Space-Based Atom Interferometry
dirigée par Éric Charron, Ernst M. Rasel et Naceur Gaaloul
Testing the Universality of Free Fall (UFF) from the 10−15 to the 10−17 level demands micrometer-scale overlap of dual-species Bose-Einstein Condensates (BECs) as well as relative velocities below 0.1 µm/s or expansion energies of the order of 10 to 50 pK.
The defense will present the characterization of atom-chip switch-off dynamics, on ground and in microgravity, and the identification of timing conditions that avoid differential center-of-mass kicks. These conditions will call for source-preparation sequences that minimize such effects.
The use of two-dimensional collimation schemes in the all-optical ATLAS experiment will be presented, and an extension to all axes will be proposed for long-baseline interferometers. The application of such a scheme to an atom-chip setup, NASA’s Cold Atom Laboratory (ISS), together with its careful analysis on 87Rb BECs, will also be shown, with a projection of 50 pK for a future mixture, a first step enabling 10−15 UFF tests.
Finally, the use of Delta-Kick Collimation on an ensemble of weakly bound Feshbach molecules will be presented as an additional way to collimate an atomic mixture, with performance comparable to that of atomic ensembles.