Collisions between Ultracold Molecules and Atoms in a Magnetic Trap

Jurgilas, S.; Chakraborty, A.; Rich, C. J. H.; Caldwell, L.; Williams, H. J.; Fitch, N. J.; Sauer, B. E.; Frye, Matthew D.; Hutson, Jeremy M.; Tarbutt, M. R.

doi:10.1103/physrevlett.126.153401

Collisions between Ultracold Molecules and Atoms in a Magnetic Trap

Jurgilas, S.; Chakraborty, A.; Rich, C. J. H.; Caldwell, L.; Williams, H. J.; Fitch, N. J.; Sauer, B. E.; Frye, Matthew D.; Hutson, Jeremy M.; Tarbutt, M. R.

Authors

S. Jurgilas

A. Chakraborty

C. J. H. Rich

L. Caldwell

H. J. Williams

N. J. Fitch

B. E. Sauer

Matthew Frye matthew.frye@durham.ac.uk
Academic Visitor

Professor Jeremy Hutson j.m.hutson@durham.ac.uk
Professor

M. R. Tarbutt

Abstract

We prepare mixtures of ultracold CaF molecules and Rb atoms in a magnetic trap and study their inelastic collisions. When the atoms are prepared in the spin-stretched state and the molecules in the spin-stretched component of the first rotationally excited state, they collide inelastically with a rate coefficient k 2 = ( 6.6 ± 1.5 ) × 10 − 11 cm 3 / s at temperatures near 100 μ K . We attribute this to rotation-changing collisions. When the molecules are in the ground rotational state we see no inelastic loss and set an upper bound on the spin-relaxation rate coefficient of k 2 < 5.8 × 10 − 12 cm 3 / s with 95% confidence. We compare these measurements to the results of a single-channel loss model based on quantum defect theory. The comparison suggests a short-range loss parameter close to unity for rotationally excited molecules, but below 0.04 for molecules in the rotational ground state.

Citation

Jurgilas, S., Chakraborty, A., Rich, C., Caldwell, L., Williams, H., Fitch, N., …Tarbutt, M. (2021). Collisions between Ultracold Molecules and Atoms in a Magnetic Trap. Physical Review Letters, 126(15), Article 153401. https://doi.org/10.1103/physrevlett.126.153401

Journal Article Type	Article
Acceptance Date	Mar 4, 2021
Online Publication Date	Apr 13, 2021
Publication Date	Apr 16, 2021
Deposit Date	May 6, 2021
Publicly Available Date	Sep 30, 2021
Journal	Physical Review Letters
Print ISSN	0031-9007
Electronic ISSN	1079-7114
Publisher	American Physical Society
Peer Reviewed	Peer Reviewed
Volume	126
Issue	15
Article Number	153401
DOI	https://doi.org/10.1103/physrevlett.126.153401

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Copyright Statement
Reprinted with permission from the American Physical Society: Jurgilas, S., Chakraborty, A., Rich, C. J. H., Caldwell, L., Williams, H. J., Fitch, N. J., Sauer, B. E., Frye, Matthew D., Hutson, Jeremy M. & Tarbutt, M. R. (2021). Collisions between Ultracold Molecules and Atoms in a Magnetic Trap. Physical Review Letters 126(15): 153401. © (2021) by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.