Optical lattice clocks with weakly bound molecules

TL;DR

This paper proposes a novel optical molecular clock using bosonic $^{174}$Yb$_2$ molecules, leveraging weakly bound states and magnetic induction to achieve high sensitivity and precision in measuring fundamental constants.

Contribution

It introduces a new approach to molecular clocks with bosonic species, utilizing weakly bound molecules and magnetic induction of forbidden transitions, supported by recent scattering data.

Findings

Feasible magnetically induced Rabi frequencies similar to atomic clocks

Potential for Hz-level molecular spectroscopy

Identification of vibrational levels for clock transitions

Abstract

Optical molecular clocks promise unparalleled sensitivity to the temporal variation of the electron-to-proton mass ratio and insight into possible new physics beyond the Standard Model. We propose to realize a molecular clock with bosonic $^{174}$Yb$_2$ molecules, where the forbidden $^1$S$_0$$\rightarrow$$^3$P$_0$ clock transition would be induced magnetically. The use of a bosonic species avoids possible complications due to hyperfine structure present in fermionic species. While direct clock line photoassociation would be challenging, weakly bound ground state molecules could be produced by STIRAP and used instead. The recent scattering measurements [L. Franchi, et al. New J. Phys 19, 103037 (2017)] enable us to determine the positions of target $^1$S$_0$+$^3$P$_0$ vibrational levels and calculate the Franck-Condon factors for clock transitions between ground and excited molecular states. The resulting magnetically induced Rabi frequencies are similar to those for atoms hinting that an experimental realization is feasible. A successful observation could pave the way towards Hz-level molecular spectroscopy.