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THU: Thursday Contributed Sessions

THU 13: Poster Session: Applications

THU 13.54: Poster

Thursday, September 11, 2025, 16:30–18:30, ZHG Foyer 1. OG

Rotational state preparation of CaOH⁺ — •Miriam Kautzky, Brandon Furey, Zhenlin Wu, Mariano Monsalve, Andrea Turci, René Nardi, Tim Duka, and Philipp Schindler — Institut für Experimentalphysik, Universität Innsbruck, Austria

Molecules provide complex degrees of freedom not available in atoms. In particular, the quantum mechanical rotation of molecules is a promising resource for quantum technologies, and enables efficient quantum error correction (QEC) codes [1]. Preparing molecules in pure rotational states is a necessary step toward implementing such codes. For this, we aim to cool molecules into low rotational states and control them precisely with Raman interactions. We are developing an experimental setup capable of achieving rotational-state cooling and state preparation of CaOH⁺ ions with broadband laser pulses, even outside cryogenic environments. The approach is based on driving rovibrational transitions using spectrally shaped broadband laser pulses. Shaping allows selective population transfer between rotational levels, enabling rotational cooling. It requires high spectral resolution and precise control of the laser spectrum to target only specific transitions. While rotational cooling to the ground state has been demonstrated before [2], precise control over rotational states, particularly in polyatomic molecules, remains much less explored. Successful implementation of rotational state control could enable exploration of quantum information processing and QEC with trapped molecular ions.
[1] B. Furey et al., Quantum 8, 1578 (2024)
[2] T. Schneider et al., Nature Phys 6, 275 (2010)

Keywords: Trapped ions; Molecular ions; Spectral pulse shaping; Rotational-state control