Quenched Magneto-association of Ultracold Feshbach Molecules

Abstract

We study enhanced magneto-association of atoms into weakly-bound molecules near a Feshbach resonance using a quench preparatory stage. In anticipation of experiments with NASA's Cold Atom Laboratory aboard the International Space Station, we assume as a baseline a dual-species (${}^{87}$Rb and ${}^{41}$K) gas in a parameter regime enabled by a microgravity environment. This includes subnanokelvin temperatures and dual-species gases at densities as low as 10${}^8$/cm${}^3$. Our studies indicate that, in such a regime, traditional magneto-association schemes are inefficient due to the weak coupling between atomic and molecular states at low-densities, thus requiring extremely long magnetic field sweeps. To address this issue we propose a modified scheme where atoms are quenched to unitarity before proceeding with magneto-association. This substantially improves molecular formation, allowing for up to $80\%$ efficiency, and within time-scales much shorter than those associated to atomic and molecular losses. We show that this scheme also applies at higher densities, therefore proving to be of interest to ground-based experiments as well.

10 pages, 6 figures

References in corpus (17)

• A High Phase-Space-Density Gas of Polar Molecules
• Observation of molecules produced from a Bose-Einstein condensate
• Observation of heteronuclear atomic Efimov resonances
• Observation of Heteronuclear Feshbach Molecules from a ${}^{85}$Rb - ${}^{87}$Rb gas
• Ultracold molecules: new probes on the variation of fundamental constants
• Adiabatic association of ultracold molecules via magnetic field tunable interactions
• Association of ultracold double-species bosonic molecules
• Spectrum and Dynamics of the BCS-BEC crossover from a few-body perspective
• Accurate near-threshold model for ultracold KRb dimers from interisotope Feshbach spectroscopy
• Enhancement of variation of fundamental constants in ultracold atom and molecule systems near Feshbach resonances
• Efficient creation of molecules from a cesium Bose-Einstein condensate
• The Efimov effect for three interacting bosonic dipoles
• Bound-state signatures in quenched Bose-Einstein condensates
• Ultracold molecules: vehicles to scalable quantum information processing
• Association of molecules using a resonantly modulated magnetic field
• Enhanced association and dissociation of heteronuclear Feshbach molecules in a microgravity environment
• Effective Control of Cold Collisions with Radio Frequency Fields

Cited by in corpus (1)

• Delta-Kick Collimation of Heteronuclear Feshbach Molecules