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  • Open Access

Spin Interferometry in a Beam of Ultracold Molecules

R. A. Jenkins*, M. T. Ziemba*, F. J. Collings, X. S. Zheng, F. Castellini, E. Wursten, J. Lim†, B. E. Sauer, and M. R. Tarbutt‡

  • *These authors contributed equally to this work.
  • †Contact author: j.lim@imperial.ac.uk
  • ‡Contact author: m.tarbutt@imperial.ac.uk
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Phys. Rev. Lett. 136, 253401 – Published 23 June, 2026

DOI: https://doi.org/10.1103/6g7x-y15q

Abstract

We describe a spin interferometer using ultracold YbF molecules and develop the complete set of techniques needed to measure the electron’s electric dipole moment, de, with this apparatus. The molecules are cooled in an optical molasses and prepared in a single internal quantum state. A Raman transition prepares a spin superposition that evolves in parallel magnetic and electric fields before a second Raman transition maps the phase onto the populations of two hyperfine states. These populations are read out using detectors that have spatial and temporal resolution and approach unit efficiency. We characterize the efficiencies and fidelities of all these steps and evaluate the sensitivity of this approach to measuring de.

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Phys. Rev. Lett. 136, 253401– Published 23 June, 2026
  • Received 31 January 2026
  • Accepted 22 May 2026
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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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