Nonadiabatic effects in ultracold strontium ``physicist's molecules'' via anomalous linear, quadratic, and higher order Zeeman shifts

Weakly bound ultracold Sr$_2$ molecules provide a rich testing ground for gaining insight into the nature of molecular bonding. We present measurements of quadratic Zeeman shifts for weakly bound molecules which scale roughly cubically with molecule size and are over a millionfold enhanced compared to free strontium atoms. From the anomalous linear shifts we obtain mixing angles for the molecular states. The nature of long-range molecular potentials and nonadiabatic Coriolis coupling explain how these non-intuitive effects arise. At large magnetic fields, cubic and quartic Zeeman shifts are clearly present, revealing higher-order mixing with nearby states. Methods of precision spectroscopy and imaging of the molecules in an optical lattice will be discussed.