Quantum logic control and precision measurements of molecular ions in a ring trap: An approach for testing fundamental symmetries

This paper presents an experimental platform designed to facilitate quantum logic control of polar molecular ions in a segmented ring ion trap, paving the way for precision measurements. This approach focuses on achieving near-unity state preparation and detection, as well as long spin-precession coherence. A distinctive aspect lies in separating state preparation and detection conducted in a static frame from parity-selective spin precession in a rotating frame. Moreover, the method is designed to support spatially and temporally coincident measurements on multiple ions prepared in states with different sensitivity to the new physics of interest. This provides powerful techniques to probe and minimize potential sources of systematic error. While the primary focus of this paper is on detecting the electron's electric dipole moment (eEDM) using ${}_{232}\mathrm{ThF}_{+}$ ions, the proposed methodology holds promise for broader applications, particularly with ion species that exhibit enhanced sensitivity to the nuclear magnetic quadruple moment (nMQM).