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Long rotational coherence times of molecules in a magnetic trap

Caldwell, L.; Williams, H.J.; Fitch, N.J.; Aldegunde, J.; Hutson, J.M.; Sauer, B.E.; Tarbutt, M.R.

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L. Caldwell

H.J. Williams

N.J. Fitch

J. Aldegunde

B.E. Sauer

M.R. Tarbutt


Polar molecules in superpositions of rotational states exhibit long-range dipolar interactions, but maintaining their coherence in a trapped sample is a challenge. We present calculations that show many laser-coolable molecules have convenient rotational transitions that are exceptionally insensitive to magnetic fields. We verify this experimentally for CaF where we find a transition with sensitivity below 5 Hz G−1 and use it to demonstrate a rotational coherence time of 6.4(8) ms in a magnetic trap. Simulations suggest it is feasible to extend this to more than 1 s using a smaller cloud in a biased magnetic trap.


Caldwell, L., Williams, H., Fitch, N., Aldegunde, J., Hutson, J., Sauer, B., & Tarbutt, M. (2020). Long rotational coherence times of molecules in a magnetic trap. Physical Review Letters, 124(6), Article 063001.

Journal Article Type Article
Acceptance Date Dec 17, 2019
Online Publication Date Feb 10, 2020
Publication Date Feb 28, 2020
Deposit Date Jan 23, 2020
Publicly Available Date Feb 13, 2020
Journal Physical Review Letters
Print ISSN 0031-9007
Electronic ISSN 1079-7114
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 124
Issue 6
Article Number 063001
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Published Journal Article (447 Kb)

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Copyright Statement
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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