JILA / NIST Boulder (US)
Tuesday, Jul 19, 3:50 PM
A tunable spin Hamiltonian of dipolar moleculesA degenerate Fermi gas of polar molecules  sets the stage to explore novel molecular dynamics. An external electric field is used to tune the elastic dipolar interaction by orders of magnitude while suppressing reactive loss. Efficient dipolar evaporation leads to the onset of quantum degeneracy in two-dimensional optical traps . The electric field tuning of the rotational energy also produces sharp collision resonances, giving rise to three orders-of-magnitude modulation of the chemical reaction rate .
The precise control of electric field facilitates the preparation and addressing of isolated, individual two-dimensional layers of molecules with a free choice of rotational states. Spin exchange between molecules of neighboring layers occurs through the long-range dipolar interaction, demonstrating quantum-state engineered stereo chemical reaction . Meanwhile, these interacting molecules in 2D are used to realize a fully tunable spin Hamiltonian, with both the Ising and spin exchange interactions precisely controlled via the electric field strength, orientation, and internal spin state. This work establishes an itinerant molecular spin platform to explore phenomena such as spin entanglement and spin transport mediated by the strong and tunable dipolar interaction.
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