Abstract
Vibrational overtones in deeply-bound molecules are sensitive probes for variation of the proton-to-electron mass ratio μ . In nonpolar molecules, these overtones may be driven as two-photon transitions. Here, we present procedures for experiments with 16 O 2 + , including state-preparation through photoionization, a two-photon probe, and detection. We calculate transition dipole moments between all X 2 Π g vibrational levels and those of the A 2 Π u excited electronic state. Using these dipole moments, we calculate two-photon transition rates and AC-Stark-shift systematics for the overtones. We estimate other systematic effects and statistical precision. Two-photon vibrational transitions in 16 O 2 + provide multiple routes to improved searches for μ variation.
Highlights
Even simple molecules contain a rich set of internal degrees of freedom
Electric-dipole coupling to other excited electronic states provides a mechanism for driving two-photon transitions [28,30,39,40]
We lay out potential experiments using such two-photon vibrational overtones
Summary
Even simple molecules contain a rich set of internal degrees of freedom. When these internal states are controlled at the quantum level, they have many applications in fundamental physics [1,2]. This quantity is sometimes called the absolute enhancement factor Both vibrational and rotational degrees of freedom have sensitivity to μ variation because both involve the nuclei moving. The absence of opposite-parity states forbids electric-dipole (E1) transitions between vibrational or rotational levels within the same electronic state This absence suppresses many electric-field-related systematic effects without the need to average over multiple transitions [33,38]. This means that any transition between vibrational states within X 2 Π g requires some higher-order process. Electric-dipole coupling to other excited electronic states provides a mechanism for driving two-photon transitions [28,30,39,40] In this manuscript, we lay out potential experiments using such two-photon vibrational overtones. With fewer ions and a quantum-logic scheme, the system is capable of measurements several orders of magnitude below the present best limit
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
