Spin-conservation propensity rule for three-body recombination of ultracold Rb atoms

Abstract

We explore the physical origin and the general validity of a propensity rule for the conservation of the hyperfine spin state in three-body recombination. This rule was recently discovered for the special case of ${}^{87}$Rb with its nearly equal singlet and triplet scattering lengths. Here, we test the propensity rule for ${}^{85}$Rb for which the scattering properties are very different from ${}^{87}$Rb. The Rb${}_2$ molecular product distribution is mapped out in a state-to-state fashion using REMPI detection schemes which fully cover all possible molecular spin states. Interestingly, for the experimentally investigated range of binding energies from zero to $\sim 13\text{GHz}\times h$ we observe that the spin-conservation propensity rule also holds for ${}^{85}$Rb. From these observations and a theoretical analysis we derive an understanding for the conservation of the hyperfine spin state. We identify several criteria to judge whether the propensity rule will also hold for other elements and collision channels.

10 pages, 9 figures, including Supplemental Material

References in corpus (5)

• Hyperfine, rotational, and vibrational structure of the triplet ground state of Rb molecules
• Precision test of statistical dynamics with state-to-state ultracold chemistry
• Feshbach resonances in ultracold 85Rb
• Quantum spin state selectivity and magnetic tuning of ultracold chemical reactions of triplet alkali-metal dimers with alkali-metal atoms
• The multichannel nature of three-body recombination for ultracold ${}^{39}$K

Cited by in corpus (3)

• Signatures of Non-universal Quantum Dynamics of Ultracold Chemical Reactions of Polar Alkali-dimer Molecules with Alkali-metal Atoms: Li(${}^2$S) +NaLi($a^3{\Sigma }^{+}$) $\to$ Na(${}^2$S) + Li${}_2$($a^3{\Sigma }_u^{+}$)
• Energy-scaling of the product state distribution for three-body recombination of ultracold atoms
• Calibrating the momentum width of a trapped Bose-Einstein condensate by one-dimensional optical lattice pulse sequences