Seminarium Optyczne

Despite tremendous progress in direct laser cooling of molecules, the only strategy so far able to deliver molecular gases at high phase-space density relies on the assembly from pre-cooled atoms in a two-step process: atom pairs are first converted into weakly bound molecules across a Feshbach resonance and later transferred to the absolute molecular ground state via stimulated Raman adiabatic passage. However, this method has so far been experimentally demonstrated only for bi-alkali systems with singlet electronic ground states.In my talk, I will initially review our results, in collaboration with M. Tomza’s group (UWarsaw), on the association of alkali lithium and transition-metal chromium into polar paramagnetic molecules [1], and preliminary benchmarks of quantum chemistry methods on Cr-bearing diatomics. I will then focus on our recent joint proposal [2] for next-generation searches for new physics based on high-spin, Σ-state, polar molecules in the ultracold regime. I will explain how these can be realized by assembly of chromium and ytterbium atoms into YbCr and describe their favorable properties from the experimental point of view. [1] S. Finelli et al., PRX Quantum 5, 020358 (2024)[2] A. Ciamei et al., arXiv:2507.16760

Despite tremendous progress in direct laser cooling of molecules, the only strategy so far able to deliver molecular gases at high phase-space density relies on the assembly from pre-cooled atoms in a two-step process: atom pairs are first converted into weakly bound molecules across a Feshbach resonance and later transferred to the absolute molecular ground state via stimulated Raman adiabatic passage. However, this method has so far been experimentally demonstrated only for bi-alkali systems with singlet electronic ground states.In my talk, I will initially review our results, in collaboration with M. Tomza’s group (UWarsaw), on the association of alkali lithium and transition-metal chromium into polar paramagnetic molecules [1], and preliminary benchmarks of quantum chemistry methods on Cr-bearing diatomics. I will then focus on our recent joint proposal [2] for next-generation searches for new physics based on high-spin, Σ-state, polar molecules in the ultracold regime. I will explain how these can be realized by assembly of chromium and ytterbium atoms into YbCr and describe their favorable properties from the experimental point of view.[1] S. Finelli et al., PRX Quantum 5, 020358 (2024)[2] A. Ciamei et al., arXiv:2507.16760