Fachbeirat 2022

Experimental advances in the quest for perfect enantiomer-specific state control of cold molecules

Not scheduled

20m

Speaker

Mr Johannes Bischoff (Fritz-Haber-Institut der Max-Planck-Gesellschaft)

Description

We explore sophisticated spectroscopic schemes in order to overcome previous limitations in the transfer efficiency of enantiomer-specific state transfer (ESST).

The ESST method was recently developed using tailored microwave fields [1]. It allows to populate or depopulate a rotational state of a chosen enantiomer, providing a way of quantum-controlled chiral separation.

One main limitation of ESST is the initial thermal population of the involved rotational levels, which prevails even for low temperatures around 1 Kelvin. We have recently shown that this can be largely solved by depleting the population in the target excited rotational level [2]. We are investigating extensions to this scheme resulting in both upper states to be initially empty, paving the way to perfect ESST for rotational states connected to the absolute ground state. Another limitation is the degeneracy of the rotational states with respect to the orientational quantum number MJ, which plays a role whenever the initial state is not the absolute ground state. We explore specialized excitation pulse schemes to allow for full enantiomer-specific control despite this degeneracy [2].

The experimentally achieved enantiomer-specific transfer efficiency was approximately 20% below the theoretically expected value. We attribute this at least partially to imperfections in the microwave polarizations and their respective orthogonality. We show a method to experimentally determine the polarization of microwave fields in-situ by quantitative analysis of molecular Rabi oscillations. This helps to understand and correct the effective field polarization in the interaction region.

In addition, we explore different molecule candidates for future experiments using low- and high-resolution electronic spectroscopy.

[1] S. Eibenberger, J. Doyle, D. Patterson, Phys. Rev. Lett. 118, 123002 (2017)
[2] J. H. Lee, J. Bischoff, A. O. Hernandez-Castillo, B. Sartakov, G. Meijer, and S. Eibenberger-Arias, Phys. Rev. Lett. 128, 173001 (2022)
[3] Leibscher, M., Pozzoli, E., Pérez, C. et al. Full quantum control of enantiomer-selective state transfer in chiral molecules despite degeneracy. Commun Phys 5, 110 (2022).