- Physical Review Journals
All JournalsPhysics Magazine

Physical Review Research

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Letter
  • Open Access

Laser-cooled BaF137 molecules for measuring nuclear-spin-dependent parity violation

Felix Kogel1, Tatsam Garg1,2, Marian Rockenhäuser1,2, and Tim Langen1,2,*

  • 15. Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
  • 2Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, A-1020 Vienna, Austria

  • *Contact author: tim.langen@tuwien.ac.at
PDF

Phys. Rev. Research 7, L022041 – Published 22 May, 2025

DOI: https://doi.org/10.1103/PhysRevResearch.7.L022041

Abstract

We demonstrate optical cycling and transverse laser cooling of a beam of fermionic BaF137 molecules. Their high masses and nuclear spins make these molecules sensitive probes for parity violation and properties of the weak interaction. However, the nuclear spins also lead to a quasiclosed cycling transition currently involving up to 112 levels, which significantly exceeds the complexity in other laser-cooled molecules. Optical cycling and cooling are facilitated through carefully designed optical spectra tailored to this molecular structure. Our results pave the way for efficient state preparation, detection, and cooling in precision measurements using this species and other similar species.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (64)

  1. J. J. Hudson, D. M. Kara, I. J. Smallman, B. E. Sauer, M. R. Tarbutt, and E. A. Hinds, Improved measurement of the shape of the electron, Nature (London) 473, 493 (2011).
  2. V. Andreev, D. G. Ang, D. DeMille, J. M. Doyle, G. Gabrielse, J. Haefner, N. R. Hutzler, Z. Lasner, C. Meisenhelder, B. R. O'Leary, C. D. Panda, A. D. West, E. P. West, X. Wu, and A. Collaboration, Improved limit on the electric dipole moment of the electron, Nature (London) 562, 355 (2018).
  3. T. S. Roussy, L. Caldwell, T. Wright, W. B. Cairncross, Y. Shagam, K. B. Ng, N. Schlossberger, S. Y. Park, A. Wang, J. Ye, and E. A. Cornell, An improved bound on the electron's electric dipole moment, Science 381, 46 (2023).
  4. A. Shelkovnikov, R. J. Butcher, C. Chardonnet, and A. Amy-Klein, Stability of the proton-to-electron mass ratio, Phys. Rev. Lett. 100, 150801 (2008).
  5. C. Chin, V. V. Flambaum, and M. G. Kozlov, Ultracold molecules: New probes on the variation of fundamental constants, New J. Phys. 11, 055048 (2009).
  6. S. Truppe, H. J. Williams, M. Hambach, L. Caldwell, N. J. Fitch, E. A. Hinds, B. E. Sauer, and M. R. Tarbutt, Molecules cooled below the Doppler limit, Nat. Phys. 13, 1173 (2017).
  7. J. Kobayashi, A. Ogino, and S. Inouye, Measurement of the variation of electron-to-proton mass ratio using ultracold molecules produced from laser-cooled atoms, Nat. Commun. 10, 3771 (2019).
  8. S. Alighanbari, G. S. Giri, F. L. Constantin, V. I. Korobov, and S. Schiller, Precise test of quantum electrodynamics and determination of fundamental constants with HD + ions, Nature (London) 581, 152 (2020).
  9. M. Germann, S. Patra, J.-P. Karr, L. Hilico, V. I. Korobov, E. J. Salumbides, K. S. E. Eikema, W. Ubachs, and J. C. J. Koelemeij, Three-body QED test and fifth-force constraint from vibrations and rotations of HD+, Phys. Rev. Res. 3, L022028 (2021).
  10. I. Doran, N. Hölsch, M. Beyer, and F. Merkt, Zero-quantum-defect method and the fundamental vibrational interval of H2+, Phys. Rev. Lett. 132, 073001 (2024).
  11. D. DeMille, J. M. Doyle, and A. O. Sushkov, Probing the frontiers of particle physics with tabletop-scale experiments, Science 357, 990 (2017).
  12. M. S. Safronova, D. Budker, D. DeMille, D. F. J. Kimball, A. Derevianko, and C. W. Clark, Search for new physics with atoms and molecules, Rev. Mod. Phys. 90, 025008 (2018).
  13. D. DeMille, N. R. Hutzler, A. M. Rey, and T. Zelevinsky, Quantum sensing and metrology for fundamental physics with molecules, Nat. Phys. 20, 741 (2024).
  14. J. Lim, J. R. Almond, M. A. Trigatzis, J. A. Devlin, N. J. Fitch, B. E. Sauer, M. R. Tarbutt, and E. A. Hinds, Laser cooled YbF molecules for measuring the electron's electric dipole moment, Phys. Rev. Lett. 120, 123201 (2018).
  15. X. Alauze, J. Lim, M. A. Trigatzis, S. Swarbrick, F. J. Collings, N. J. Fitch, B. E. Sauer, and M. R. Tarbutt, An ultracold molecular beam for testing fundamental physics, Quantum Sci. Technol. 6, 044005 (2021).
  16. R. L. McNally, I. Kozyryev, S. Vazquez-Carson, K. Wenz, T. Wang, and T. Zelevinsky, Optical cycling, radiative deflection and laser cooling of barium monohydride (Ba138H1), New J. Phys. 22, 083047 (2020).
  17. M. Rockenhäuser, F. Kogel, T. Garg, S. A. Morales-Ramírez, and T. Langen, Laser cooling of barium monofluoride molecules using synthesized optical spectra, Phys. Rev. Res. 6, 043161 (2024).
  18. Z. D. Lasner, A. Frenett, H. Sawaoka, L. Anderegg, B. Augenbraun, H. Lampson, M. Li, A. Lunstad, J. Mango, A. Nasir, T. Ono, T. Sakamoto, and J. M. Doyle, Magneto-optical trapping of a heavy polyatomic molecule for precision measurement, Phys. Rev. Lett. 134, 083401 (2025).
  19. I. Kozyryev and N. R. Hutzler, Precision measurement of time-reversal symmetry violation with laser-cooled polyatomic molecules, Phys. Rev. Lett. 119, 133002 (2017).
  20. N. J. Fitch, J. Lim, E. A. Hinds, B. E. Sauer, and M. R. Tarbutt, Methods for measuring the electron's electric dipole moment using ultracold YbF molecules, Quantum Sci. Technol. 6, 014006 (2021).
  21. L. Anderegg, N. B. Vilas, C. Hallas, P. Robichaud, A. Jadbabaie, J. M. Doyle, and N. R. Hutzler, Quantum control of trapped polyatomic molecules for eEDM searches, Science 382, 665 (2023).
  22. N. Fitch and M. Tarbutt, Laser-cooled molecules, Adv. At., Mol., Opt. Phys. 70, 157 (2021).
  23. M.-A. Bouchiat and C. Bouchiat, Parity violation in atoms, Rep. Prog. Phys. 60, 1351 (1997).
  24. The Jefferson Lab PVDIS Collaboration, Measurement of parity violation in electron–quark scattering, Nature (London) 506, 67 (2014).
  25. E. Altuntaş, J. Ammon, S. B. Cahn, and D. DeMille, Demonstration of a sensitive method to measure nuclear-spin-dependent parity violation, Phys. Rev. Lett. 120, 142501 (2018).
  26. D. Antypas, A. Fabricant, J. E. Stalnaker, K. Tsigutkin, V. V. Flambaum, and D. Budker, Isotopic variation of parity violation in atomic ytterbium, Nat. Phys. 15, 120 (2019).
  27. C. S. Wood, S. C. Bennett, D. Cho, B. P. Masterson, J. L. Roberts, C. E. Tanner, and C. E. Wieman, Measurement of parity nonconservation and an anapole moment in cesium, Science 275, 1759 (1997).
  28. W. C. Haxton, C.-P. Liu, and M. J. Ramsey-Musolf, Nuclear anapole moments, Phys. Rev. C 65, 045502 (2002).
  29. W. R. Johnson, M. S. Safronova, and U. I. Safronova, Combined effect of coherent Z exchange and the hyperfine interaction in the atomic parity-nonconserving interaction, Phys. Rev. A 67, 062106 (2003).
  30. M. G. Kozlov and L. N. Labzowsky, Parity violation effects in diatomics, J. Phys. B: At., Mol. Opt. Phys. 28, 1933 (1995).
  31. D. DeMille, S. B. Cahn, D. Murphree, D. A. Rahmlow, and M. G. Kozlov, Using molecules to measure nuclear spin-dependent parity violation, Phys. Rev. Lett. 100, 023003 (2008).
  32. E. Altuntaş, J. Ammon, S. B. Cahn, and D. DeMille, Measuring nuclear-spin-dependent parity violation with molecules: Experimental methods and analysis of systematic errors, Phys. Rev. A 97, 042101 (2018).
  33. V. A. Dzuba, V. V. Flambaum, and Y. V. Stadnik, Probing low-mass vector bosons with parity nonconservation and nuclear anapole moment measurements in atoms and molecules, Phys. Rev. Lett. 119, 223201 (2017).
  34. K. Gaul, M. G. Kozlov, T. A. Isaev, and R. Berger, Chiral molecules as sensitive probes for direct detection of P-odd cosmic fields, Phys. Rev. Lett. 125, 123004 (2020).
  35. V. V. Flambaum and I. B. Khriplovich, On the enhancement of parity nonconserving effects in diatomic molecules, Phys. Lett. A 110, 121 (1985).
  36. F. Kogel, M. Rockenhäuser, R. Albrecht, and T. Langen, A laser cooling scheme for precision measurements using fermionic barium monofluoride (Ba137F19) molecules, New J. Phys. 23, 095003 (2021).
  37. E. B. Norrgard, D. S. Barker, S. Eckel, J. A. Fedchak, N. N. Klimov, and J. Scherschligt, Nuclear-spin dependent parity violation in optically trapped polyatomic molecules, Commun. Phys. 2, 77 (2019).
  38. J. Karthein, S. M. Udrescu, S. B. Moroch, I. Belosevic, K. Blaum, A. Borschevsky, Y. Chamorro, D. DeMille, J. Dilling, R. F. Garcia Ruiz, N. R. Hutzler, L. F. Pašteka, and R. Ringle, Electroweak nuclear properties from single molecular ions in a Penning trap, Phys. Rev. Lett. 133, 033003 (2024).
  39. F. Kogel, T. Garg, M. Rockenhäuser, S. A. Morales-Ramírez, and T. Langen, Isotopologue-selective laser cooling of molecules, New J. Phys. 27, 013001 (2025).
  40. R. Albrecht, M. Scharwaechter, T. Sixt, L. Hofer, and T. Langen, Buffer-gas cooling, high-resolution spectroscopy, and optical cycling of barium monofluoride molecules, Phys. Rev. A 101, 013413 (2020).
  41. M. Rockenhäuser, F. Kogel, E. Pultinevicius, and T. Langen, Absorption spectroscopy for laser cooling and high-fidelity detection of barium monofluoride molecules, Phys. Rev. A 108, 062812 (2023).
  42. P. Aggarwal, H. L. Bethlem, A. Borschevsky, M. Denis, K. Esajas, P. A. B. Haase, Y. Hao, S. Hoekstra, K. Jungmann, T. B. Meijknecht, M. C. Mooij, R. G. E. Timmermans, W. Ubachs, L. Willmann, and A. Zapara, Measuring the electric dipole moment of the electron in BaF, Eur. Phys. J. D 72, 197 (2018).
  43. F. Kogel, T. Garg, M. Rockenhäuser, S. A. Morales-Ramírez, and T. Langen, Molecular laser cooling using serrodynes: Implementation, characterization and prospects, arXiv:2501.10725.
  44. Z. Zeng, S. Deng, S. Yang, and B. Yan, Three-dimensional magneto-optical trapping of barium monofluoride, Phys. Rev. Lett. 133, 143404 (2024).
  45. F. Kogel et al., High-resolution spectroscopy of barium monofluoride (unpublished).
  46. T. C. Steimle, S. Frey, A. Le, D. DeMille, D. A. Rahmlow, and C. Linton, Molecular-beam optical Stark and Zeeman study of the A2Π−X2Σ+ (0,0) band system of BaF, Phys. Rev. A 84, 012508 (2011).
  47. E. Pultinevicius, M. Rockenhäuser, F. Kogel, P. Groß, T. Garg, O. E. Prochnow, and T. Langen, A scalable scanning transfer cavity laser stabilization scheme based on the Red Pitaya STEMlab platform, Rev. Sci. Instrum. 94, 103004 (2023).
  48. Z. Lasner and D. DeMille, Statistical sensitivity of phase measurements via laser-induced fluorescence with optical cycling detection, Phys. Rev. A 98, 053823 (2018).
  49. J. C. Shaw, J. C. Schnaubelt, and D. J. McCarron, Resonance Raman optical cycling for high-fidelity fluorescence detection of molecules, Phys. Rev. Res. 3, L042041 (2021).
  50. B. L. Augenbraun, Z. D. Lasner, A. Frenett, H. Sawaoka, C. Miller, T. C. Steimle, and J. M. Doyle, Laser-cooled polyatomic molecules for improved electron electric dipole moment searches, New J. Phys. 22, 022003 (2020).
  51. D. Mitra, N. B. Vilas, C. Hallas, L. Anderegg, B. L. Augenbraun, L. Baum, C. Miller, S. Raval, and J. M. Doyle, Direct laser cooling of a symmetric top molecule, Science 369, 1366 (2020).
  52. N. B. Vilas, C. Hallas, L. Anderegg, P. Robichaud, A. Winnicki, D. Mitra, and J. M. Doyle, Magneto-optical trapping and sub-Doppler cooling of a polyatomic molecule, Nature (London) 606, 70 (2022).
  53. A. D. Kudashov, A. N. Petrov, L. V. Skripnikov, N. S. Mosyagin, T. A. Isaev, R. Berger, and A. V. Titov, Ab initio study of radium monofluoride (RaF) as a candidate to search for parity- and time-and-parity–violation effects, Phys. Rev. A 90, 052513 (2014).
  54. Y. Hao, P. Navrátil, E. B. Norrgard, M. Iliaš, E. Eliav, R. G. E. Timmermans, V. V. Flambaum, and A. Borschevsky, Nuclear spin-dependent parity-violating effects in light polyatomic molecules, Phys. Rev. A 102, 052828 (2020).
  55. N. R. Hutzler, Polyatomic molecules as quantum sensors for fundamental physics, Quantum Sci. Technol. 5, 044011 (2020).
  56. A. Jadbabaie, Y. Takahashi, N. H. Pilgram, C. J. Conn, Y. Zeng, C. Zhang, and N. R. Hutzler, Characterizing the fundamental bending vibration of a linear polyatomic molecule for symmetry violation searches, New J. Phys. 25, 073014 (2023).
  57. A. Touwen, J. W. F. van Hofslot, T. Qualm, R. Borchers, R. Bause, H. L. Bethlem, A. Boeschoten, A. Borschevsky, T. H. Fikkers, S. Hoekstra, K. Jungmann, V. R. Marshall, T. B. Meijknecht, M. C. Mooij, R. G. E Timmermans, W. Ubachs, L. Willmann, and NL-eEDM Collaboration, Manipulating a beam of barium fluoride molecules using an electrostatic hexapole, New J. Phys. 26, 073054 (2024).
  58. V. V. Flambaum and D. W. Murray, Anapole moment and nucleon weak interactions, Phys. Rev. C 56, 1641 (1997).
  59. A. L. Collopy, S. Ding, Y. Wu, I. A. Finneran, L. Anderegg, B. L. Augenbraun, J. M. Doyle, and J. Ye, 3D magneto-optical trap of yttrium monoxide, Phys. Rev. Lett. 121, 213201 (2018).
  60. C. Höhle, H. Hühnermann, T. Meier, H. Ihle, and R. Wagner, Nuclear moments and optical isotope shift of radioactive Ba133, Phys. Lett. B 62, 390 (1976).
  61. M. Denis, Y. Hao, E. Eliav, N. R. Hutzler, M. K. Nayak, R. G. E. Timmermans, and A. Borschesvky, Enhanced P,T-violating nuclear magnetic quadrupole moment effects in laser-coolable molecules, J. Chem. Phys. 152, 084303 (2020).
  62. Y. Zeng, A. Jadbabaie, A. N. Patel, P. Yu, T. C. Steimle, and N. R. Hutzler, Optical cycling in polyatomic molecules with complex hyperfine structure, Phys. Rev. A 108, 012813 (2023).
  63. S. M. Udrescu, A. J. Brinson, R. F. G. Ruiz, K. Gaul, R. Berger, J. Billowes, C. L. Binnersley, M. L. Bissell, A. A. Breier, K. Chrysalidis, T. E. Cocolios, B. S. Cooper, K. T. Flanagan, T. F. Giesen, R. P. de Groote, S. Franchoo, F. P. Gustafsson, T. A. Isaev, A. Koszorús, G. Neyens et al., Isotope shifts of radium monofluoride molecules, Phys. Rev. Lett. 127, 033001 (2021).
  64. W. C. Haxton and B. R. Holstein, Hadronic parity violation, Prog. Part. Nucl. Phys. 71, 185 (2013).

Outline

Information

Phys. Rev. Research 7, L022041– Published 22 May, 2025
  • Received 10 February 2025
  • Accepted 25 April 2025
Crossmark - Check for updates button
Creative Commons Logo

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.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation