Seminarium Optyczne

Weakly bound molecules promise unparalleled sensitivity to temporal variations of the proton-to-electron mass ratio [1] and in searches for new interactions beyond the Standard Model [2]. Both applications, however, rely on measurements of vibrational state positions of yet unrealized accuracy. To mitigate this, we propose to observe clock 1S0-3P0 transitions in weakly bound bosonic 174Yb2 molecules [3]. As in bosonic atomic clocks, a small transition dipole moment could be induced by means of a weak external magnetic field [4]. The positions of molecular clock lines can be determined to high accuracy: ground bound state positions have been measured with two-color photoassociation spectroscopy [5], while excited 1S0+3P0 0u- vibrational states can be predicted accurately using an interaction potential with ab initio long range parameters [6] and fitted to the recently measured 174Yb 1S0-3P0 scattering length [7]. The necessary ground state Yb2 molecules could be efficiently produced by STIRAP. Thanks to favorable Franck-Condon factors the magnetically induced molecular Rabi frequencies can be comparable to the atomic Rabi frequencies under same laser intensities and magnetic fields. Using new ab initio potentials [8] we evaluate the sensitivity of the excited clock states to changes in the proton-to-electron mass ratio and explore the prospects of using an ytterbium molecular clock for searches of temporal variation of this fundamental constant.