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A: Fachverband Atomphysik

A 29: Poster: Ultra-cold atoms, ions and BEC (with Q)

A 29.2: Poster

Wednesday, March 20, 2013, 16:00–18:30, Empore Lichthof

Two-channel Bose-Hubbard model of atoms at a Feshbach resonance — •Philipp-Immanuel Schneider and Alejandro Saenz — AG Moderne Optik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin

Based on the analytic model of Feshbach resonances in harmonic traps described in [1] a Bose-Hubbard model is introduced that allows for the accurate description of two atoms in an optical lattice at a Feshbach resonance with only a small number of Bloch bands. The approach circumvents the problem that the eigenenergies in the presence of a delta-like coupling do not converge to the correct energies, if an uncorrelated basis is used.

Furthermore, we describe a possibility to realistically mimic Feshbach resonances within non-perturbative single-channel approaches by using a square-well interaction potential. This allows to compare the predictions of the Bose-Hubbard model to non-perturbative calculations of the stationary eigenenergies and the dynamical behavior of the atoms during an acceleration of the optical lattice.
[1] P.-I. Schneider and A. Saenz, Phys. Rev. A 83, 030701(R) (2011).