Title: Probing Atomic Interactions near a Feshbach Resonance

R. L. Compton, Y.-J. Lin, K. Jiminez-Garcia, and I. B. Spielman

Affiliation: Laser Cooling Group, NIST Gaithersburg, MD 20899.

Quantum degenerate gases, for example Bose-Einstein condensates, are non-ideal gases in which interaction energies can be comparable to the kinetic energy.  Recently it has become possible to increase interaction energies using a magnetically tunable Feshbach resonance.  A Feshbach resonance leads to an enhancement of the atomic scattering length for an “open channel” scattering state, due to a (near) degeneracy with a “closed channel” molecular bound state.  Here, we study a Feshbach resonance near 1007 G in ⁸⁷Rb.  Within 1 G of the resonance, we observe an enhancement of the three body loss rate constant, K₃, by as much as three orders of magnitude.  We compare this observation to a direct measurement of the scattering length.  Finally, we use a spectroscopic technique to map the energy of the bound state relative to the unbound state as a function of magnetic field.  This work builds on a new paradigm in which dilute atomic gases can be used to simulate condensed matter systems, where strong interactions give rise to interesting correlations.

CATEGORY: Physics

Mentors Name:  Ian B. Spielman

Atomic Physics Division, 842

B253, Building 216, Mail stop 8424

Tel: x8244

Fax:

Email:compton@physics.nist.gov

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