Towards precision spectroscopy on single trapped molecular ions

We are currently setting up an experimental apparatus for the investigation of molecular ions. The main goal of the experiment is precision spectroscopy on a vibrational overtone transition of a single molecular ion to probe for new physics effects such as a possible variation of fundamental constants. For this purpose, we are implementing quantum logic spectroscopy that was already successfully used for the aluminum optical clock [1] and the first clock based on highly charged ion [2]. We plan to implement a modified version of the classical quantum logic spectroscopy by using optical forces from bichromatic Raman interactions on the molecular ion, that allow to entangle the internal state of the molecule with the motional state [3]. The motional state is shared between the molecule and a co-trapped atomic ion and can therefore be used as a bus to transfer information from one ion to the other. Detection of the motional excitation on the atomic ion will allow us to infer the molecules internal state [4].

As we move toward overtone spectroscopy of single molecular ions, we are also investigating new techniques for time and frequency metrology. We have developed a quantum metrological measurement method based on Fock states and demonstrated frequency measurements below the standard quantum limit [5].

On my poster I will show the status of the experiments and present some ideas for experiments with trapped atomic and molecular ions in the context of time and frequency measurements.

References

[1] S. M. Brewer et al., Physical Review Letters 123, 033201 (2019)

[2] S. A. King et al., Nature 611, 43-47 (2022)

[3] F. Wolf et al. arXiv:2002.05584 (2020)

[4] F. Wolf et al., Nature 530, 457-460 (2016)

[5] F. Wolf et al., Nature Communications 10 (1), 1-8 (2019)