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Sat, January 1, 2011

Spin gradient demagnetization cooling of ultracold atoms

We have demonstrated a new cooling method in which a time-varying magnetic field gradient is applied to an ultracold spin mixture [1].  We prepare a two-component cloud of rubidium atoms, either in the superfluid or Mott insulator phase, in a strong field gradient separating the two components with a narrow mixed region between the pure-spin...

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Sat, January 1, 2011

Making Van Der Waals Molecules

Van der waals molecules involving helium as a partner are typically very weakly bound and exist only in non-equilibrium situations. Here, through re-analysis of Ag atom magnetic trap loss, a general method for creating, in equilibrium, a host of vdW molecules in the very low temperature (and high cooling capacity) conditions of dilution refrigerator cooled...

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Sat, January 1, 2011

Low-inelastic-rate Atom-Molecule Collisions in a Magnetic Trap

The study of low-temperature molecular collisions is a key step to understanding the fundamental processes in archetypal few-body systems, but also as a stepping stone to further cooling, whether sympathetic or evaporative. With the aim of building on our buffer-gas-loaded BEC work with metastable helium, we studied, both theoretically and experimentally, the collisional properties of...

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Sat, January 1, 2011

A Cold and Slow Molecular Beam

Due to the rich internal structures and the long range, anisotropic, and tunable interaction of polar molecules, increasingly efforts have been devoted to producing cold polar molecules for studying quantum simulation, cold, controlled chemistry, and precision measurements. We reported producing a cold, slow calcium monohydride molecular beam using a two-stage cryogenic buffer gas cell. This...

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Sat, January 1, 2011

Quantum degenerate Bose-Fermi mixture of chemically different atomic species with widely tunable interactions

We have created a quantum degenerate Bose-Fermi mixture of 23Na and 40K with widely tunable interactions via broad interspecies Feshbach resonances. Twenty Feshbach resonances between 23Na and 40K were identified. The large and negative triplet background scattering length between 23Na and 40K causes a sharp enhancement of the fermion density in the presence of a...

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