Abstract:

Precision spectroscopy of molecules promises a wealth of interesting applications e.g. for better determination of natural constants, for tests of fundamental particle theories, and for qubit realizations. Unfortunately, most molecules do not possess closed transitions for laser cooling, crucial for obtaining temperatures low enough for exploiting these systems

A way to circumvent this issue is to work with a trapped molecular ion, and sympathetically cool its translational degrees of freedom by Coulomb interaction with a co-trapped atomic ion possessing suitable transitions for laser cooling.

Doppler laser cooling will lead to the formation of a two-ion Coulomb crystal, which can then be prepared in the ground state of motion via the sideband cooling technique.

Having prepared this system, it is possible to detect a change of the internal state of the molecular ion by monitoring the common motional state on the atomic ion, a technique called photon-recoil spectroscopy.

Although this experiment only involves 2 particles (apart from photons) it is interesting in a CCQ context since applied ideas and techniques such as ion trapping, ground state cooling, temperature and mass measurements, and ion/neutral interactions are essential for the future hybrid experiments on interactions between a single ion and an atomic gas.