Progress towards observing dipole-phonon quantum logic in CaO⁺ - Ca⁺ ion chain

Dipole-phonon quantum logic uses the interaction between the dipole of a molecular ion in an ion chain and the quantized motion of the ion chain to prepare and measure quantum information in molecular ion states. Here we report our progress on searching for the dipole-phonon interaction in a two-ion chain of CaO⁺ and Ca⁺. The Λ-doublet of CaO⁺ in its ground rotational state has a calculated splitting of 2π×450 kHz. By tuning the frequency of the trap to be resonant with the \Lambda doublet transition, the molecular dipole will couple to the axial secular motion of the ion chain. This coupling can be observed by using co-trapped Ca⁺ to detect changes in the phonon number. Challenges such as blackbody radiation and low population of the ground rotational state under room temperature are simulated and analyzed. Preliminary results will also be discussed.