Speaker
Description
In recent years, molecules have emerged as valuable precision metrology platforms for probing symmetry violations in fundamental physics. Heavy dipolar molecular species such as barium monofluoride (BaF) are particularly attractive, as their sensitivity to potential new physics is greatly enhanced, while remaining relatively simple to control due to their favorable molecular structure. Owing to the availability of several isotopologues, BaF in particular enables comple mentary tests of symmetry-breaking phenomena, including the search for the electron’s electric dipole moment and nuclear parity-violating effects. By per forming these measurements with various different isotopologues, it is also possible to use isotope shifts to partially sidestep the theory uncertainties arising
from nuclear physics calculations and to decouple some of the P- and T-odd
parameters being tested. To this end, we are developing an apparatus capable of precise control of these molecules, with the aim of performing trap-based measurements. In this apparatus, BaF molecules are produced in a cryogenic buffer-gas cell and subsequently laser-cooled to reduce the divergence of the molecular beam, significantly increasing the number of molecules that can be captured in a future magneto-optical trap (MOT). I will be presenting our latest developments towards such precision measurements, including isotopologue separation [1], spectroscopy [2], and the first laser cooling of fermionic 137BaF [3], which - with its 112 hyperfine levels - required the development of novel techniques for the cooling laser system [4].
[1] F. Kogel, T. Garg, M. Rockenhäuser, S. A. Morales-Ramírez, and T. Langen, New Journal of Physics, vol. 27, no. 1, p. 013 001, Jan. 2025.
[2] F. Kogel et al., Phys. Rev. A, vol. 112, p. 042 807, 4 Oct. 2025.
[3] F. Kogel, T. Garg, M. Rockenhäuser, and T. Langen, Phys. Rev. Res.,
vol. 7, p. L022041, 2 May 2025.
[4] F. Kogel, T. Garg, M. Rockenhäuser, S. A. Morales-Ramírez, and T. Langen, New Journal of Physics, vol. 27, no. 5, p. 055 001, May 2025.