Precision spectroscopy and coherent control of single molecular nitrogen ions

8 Sept 2026, 13:30
25m
Long Talk (20min) Molecular Spectroscopy Molecular Spectroscopy

Speaker

Nicolas Adrian Nuñez Barreto (University of Basel)

Description

In this work, we demonstrate the quantum control and precision spectroscopy of a clock transition in a single molecular nitrogen ion. We report the first observation of Rabi oscillations and spectra on a mid-infrared electric-quadrupole rovibrational transition in a molecular ion, thus establishing a robust platform for the coherent manipulation of high-fidelity molecular qubits and clock transitions.
Our experimental architecture utilizes a single calcium atomic ion co-trapped with the molecule in a linear Paul trap. State detection is achieved via a quantum-logic-inspired scheme based on optical lattice-induced coherent motional excitation, enabling high-fidelity, non-destructive identification of the molecular state [1]. Due to the extremely narrow linewidth of the transitions, we employ wide-range rapid adiabatic passage (RAP) scans for initial signal identification, followed by iterative RAP-based frequency narrowing to enable high-resolution Rabi spectroscopy [2].
The spectroscopic measurements are referenced to the Swiss primary frequency standard at the Swiss National Institute of Metrology (METAS) via a stabilized optical-fiber link enabling SI-traceability of measured frequencies [3]. Our results demonstrate a clear pathway toward the realization of molecular clocks, the study of state-resolved reaction dynamics, tests of fundamental physics, and the development of molecular qubits for quantum information processing.

[1] Sinhal, M., Meir, Z., Najafian, K., Hegi, G., & Willitsch, S. (2020). Quantum-nondemolition state detection and spectroscopy of single trapped molecules. Science, 367(6483), 1213-1218.
[2] Shlykov, A., Diouf, M. L., Karl, R., Roguski, M., Joshi, U. C., & Willitsch, S. (2026). Quantum-logic spectroscopy of forbidden vibrational transitions in single nitrogen molecular ions. arXiv preprint arXiv:2603.10553.
[3] Husmann, D., Bernier, L. G., Bertrand, M., Calonico, D., Chaloulos, K., Clausen, G., ... & Morel, J. (2021). SI-traceable frequency dissemination at 1572.06 nm in a stabilized fiber network with ring topology. Optics express, 29(16), 24592-24605.

Academic level Postdoctoral researcher

Authors

Nicolas Adrian Nuñez Barreto (University of Basel) Mr Umesh Chandra Joshi (University of Basel)

Co-authors

Dr Aleksandr Shlykov (University of Basel) Dr Meissa Diouf (University of Basel) Mr Mikolaj Roguski (University of Basel) Mr Richard Karl (University of Basel) Prof. Stefan Willitsch (University of Basel)

Presentation materials

There are no materials yet.