Mingyang Guo

Coherent Heteronuclear Spin Dynamics in an Ultracold Spinor Mixture.

We report the observation of coherent heteronuclear spin dynamics driven by interspecies spin-spin interaction in an ultracold spinor mixture, which manifests as periodical and well-correlated spin oscillations between two atomic species. In particular, we investigate the magnetic field dependence of the oscillations and find a resonance behavior which depends on both the linear and quadratic Zeeman effects and the spin-dependent interaction. We also demonstrate a unique knob for controlling the spin dynamics in the spinor mixture with species-dependent vector light shifts.

Collisions of ultracold 23Na87Rb molecules with controlled chemical reactivities

An experiment on ultracold polar molecules shows that there is more to be understood besides ultracold chemical reactions. The collision of molecules at ultracold temperatures is of great importance to understand the chemical interactions at the quantum regime. Although much theoretical work has been devoted to this, experimental data are only sparsely available, mainly because of the difficulty in producing ground-state molecules at ultracold temperatures. We report here the creation of optically trapped samples of ground-state bosonic sodium-rubidium molecules with precisely controlled internal states and, enabled by this, a detailed study on the inelastic loss with and without the NaRb + NaRb → Na2 + Rb2 chemical reaction. Contrary to intuitive expectations, we observed very similar loss and heating, regardless of the chemical reactivities. In addition, as evidenced by the reducing loss rate constants with increasing temperatures, we found that these collisions are already outside the Wigner region although the sample temperatures are sub-microkelvin. Our measurement agrees semiquantitatively with models based on long-range interactions but calls for a deeper understanding on the short-range physics for a more complete interpretation.

High-resolution molecular spectroscopy for producing ultracold absolute-ground-state Na23Rb87 molecules

We report a detailed molecular spectroscopy study on the lowest excited electronic states of

High-resolution Internal State Control of Ultracold

^{23}\rm{Na}^{87}\rm{Rb}

^{23}

for producing ultracold

Na

^{23}\rm{Na}^{87}\rm{Rb}

^{87}

molecules in the electronic, rovibrational and hyperfine ground state. Starting from weakly-bound Feshbach molecules, a series of vibrational levels of the

Rb Molecules

A^{1}\Sigma^{+}-b^{3}\Pi

Long-range states of the NaRb molecule near the Na(3 S-2(1/2))+Rb(5 P-2(3/2)) asymptote

coupled excited states were investigated. After resolving, modeling and interpreting the hyperfine structure of several lines, we successfully identified a long-lived level resulting from the accidental hyperfine coupling between the

Creation of an Ultracold Gas of Ground-State Dipolar ^{23}Na^{87}Rb Molecules.

0^+