Speaker
Description
The QCosmo team studies quantum states and dynamics in trapped polyatomic molecular ions with quantum logic spectroscopy (QLS). This method maps molecular transitions to a co-trapped atomic logic ion via a shared motional mode, enabling robust and efficient state readout. We focus on novel spectroscopy techniques, rovibronic state preparation and control, and the possibilities and limitations of applying quantum information processing techniques such as quantum error correction to molecular ions [B. Furey et al. Quantum 8, 1578 (2024)]. We have measured the photodissociation spectra of CaOH$^+$ [Z. Wu et al. J. Chem. Phys. 161, 044304 (2024), and more recently the infrared vibrational transition frequency in the OH stretch mode of a single trapped CaOH$^+$ molecular ion using cat state recoil spectroscopy [Z. Wu et al., arXiv:2511.19687[quant-ph] (2025)]. This method uses non-classical spin-motion-entangled cat states to amplify the detection of the recoil of a single absorbed photon via an accumulated geometric phase. We are also developing Raman QLS to enable molecular hyperfine and rotational spectroscopy and control. Ongoing work includes planning and development of a cryogenic experiment with a segmented ion trap. The segmented design enables potential splitting, allowing the realization of specific Coulomb-crystal configurations of logic and spectroscopy ions. Additionally, it facilitates shuttling operations, such that selected ions are positioned in tightly focused laser beams to perform logic operations. The cryogenic environment suppresses quantum jumps from thermal radiation and background gas collisions, thus extending ion storage and coherence times. Also under development is an ion-injection system, which introduces molecular ions into the ion trap from an external source. It comprises a quadrupole mass filter and a quadrupole deflector, enabling a highly species-selective injection as well as flexible adaptation to different molecular species. The trap dynamics can be synchronized with the molecular injection by monitoring the ion yield using a time-of-flight mass spectrometer.
| Academic level | Master's Student |
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