Enhanced association and dissociation of heteronuclear Feshbach molecules in a microgravity environment

Abstract

We study the association and dissociation dynamics of weakly bound heteronuclear Feshbach molecules using transverse RF-fields for expected parameters accessible through the microgravity environment of NASA's Cold Atom Laboratory (CAL) aboard the International Space Station, including temperatures at or below nK and atomic densities as low as 10 8 /cm 3 . We show that under such conditions, thermal and loss effects can be greatly suppressed resulting in high efficiency in both association and dissociation of Feshbach molecules with mean size exceeding 10 4 a0, and allowing for the coherence in atom-molecule transitions to be clearly observable. Our theoretical model for heteronuclear mixtures includes thermal, loss, and density effects in a simple and conceptually clear manner. We derive the temperature, density and scattering length regimes of 41 K-87 Rb that allow optimal association/dissociation efficiency with minimal heating and loss to guide future experiments with ultracold atomic gases in space.

Collective-Mode Enhanced Matter-Wave Optics

“…Obviously, our method can also be employed with attractive or tunable interactions [40] and diverging magnetic lenses [41,42]. Interactions are nowadays also exploited to establish non-classical correlations.…”

NASA’s Cold Atom Lab (CAL): system development and ground test status

“…These operations will be conducted through a collaboration of the CAL PIs and the CAL team based at JPL, with each PI allocated schedule for their experiments to be run. The proposed research will investigate applications of atom interferometry for future precision measurements in the areas of Earth observation and fundamental physics, 47 , 48 Feshbach resonances to control differential center-of-mass distributions of dual-species quantum gas mixtures, 49 , 50 bubble-shell geometries for Bose–Einstein condensates, 51 as well as few-body systems in new temperature and density regimes that are prerequisites for the next generation of Efimov experiments. 52 After the conclusion of these experiments, the instrument will either enter a decommissioning phase or, through the use of orbital replacement units, receive novel, upgraded capabilities for extended mission operation and new microgravity experiments of advancing scope and complexity.…”

The Bose-Einstein Condensate and Cold Atom Laboratory

“…a box trap generated by blue-detuned light) to create a homogeneous interaction strength over a large volume. Moreover, clouds of different atomic species perfectly overlap resulting in higher rates and efficiencies of Feshbach-molecule formation [103].…”