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SYCC: Symposium From Molecular Spectroscopy to Collision Control at the Quantum Limit

SYCC 1: From Molecular Spectroscopy to Collision Control at the Quantum Limit

SYCC 1.4: Hauptvortrag

Donnerstag, 9. März 2023, 12:30–13:00, E415

The birth of a degenerate Fermi gas of molecules — •Jun Ye — JILA, NIST and Univ Colorado, Boulder, Colorado, USA

It is an honor to help celebrate the scientific legacy of Prof. Eberhard Tiemann. Prof. Tiemann played an important role during the early stages of the first experiment in producing a high phase-space density gas of polar molecules in the absolute ground state. The experiment was jointly performed with my late colleague Prof. Deborah Jin in 2008.

In 2018 we finally produced the first degenerate Fermi gas of polar molecules, with 30,000 KRb molecules and T/T_F of 0.3. A precisely controlled electric field is applied to tune the elastic dipolar interaction by orders of magnitude while suppressing reactive losses. 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, and permitting dipolar evaporative cooling in 3D. The precise control of electric field has also allowed us to prepare and address isolated, individual two-dimensional layers of molecules with arbitrary choices of rotational state. We study exchanges of rotational angular momenta between molecules of neighboring layers through long-range dipolar interactions, demonstrating quantum-state engineered stereo chemical reaction. Meanwhile, these interacting molecules in 2D were used to realize a tunable spin Hamiltonian for quantum magnetism.