News: Research Highlights

Sat January 1, 2011

Cold Heteromolecular Dipolar Collisions

We present the first experimental observation of cold collisions between two different species of neutral polar molecules, each prepared in a single internal quantum state. Combining for the first time the techniques of Stark deceleration, magnetic trapping, and cryogenic buffer gas cooling allows the enhancement of molecular interaction time by 10,000. This has enabled an...
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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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Sat January 1, 2011

A cryogenic beam of refractory, chemically reactive molecules with expansion cooling

Atomic and molecular beams have been valuable tools for precision measurement of atomic and molecular spectra for the past several decades.  In order to achieve good signal to noise in a beam spectroscopy experiment, it is important to have high fluxes, low forward velocity (to increase interaction time), and, in the case of molecules, cold...
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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

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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Fri January 1, 2010

Probing quantum phase transitions at the single-atom level

Physicists Get an Up–Close Look at Synthetic Quantum Materials

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Fri January 1, 2010

Thermometry and Refrigeration in a Two-Component Mott Insulator of Ultracold Atoms

In this work [1], we describe and analyze theoretically the two techniques of spin-gradient thermometry and spin gradient demagnetization cooling developed earlier by our group [2, 3].
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Fri January 1, 2010

A Magnetic Gas

For decades, it has been an open question whether it is possible for a gas to show properties similar to a magnet made of iron or nickel.  Iron and nickel are ferromagnetic because they become strongly magnetized below a specific temperature, when unpaired electrons within the material spontaneously align in the same direction.

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