Düsseldorf 2007 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 56: Quantengase (Fermionen und Gemische)
Q 56.5: Talk
Thursday, March 22, 2007, 15:00–15:15, 6J
Energy spectrum of two interacting particles with unequal trapping frequencies at an optical lattice site — •Frank Deuretzbacher1, Kim Plassmeier1, Daniela Pfannkuche1, Christian Ospelkaus2, Silke Ospelkaus2, Klaus Sengstock2, and Kai Bongs2 — 1I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstr. 9, 20355 Hamburg, Germany — 2Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
We study fermionic 40K atoms interacting with bosonic 87Rb atoms at a single optical lattice site at a heteronuclear atomic Feshbach resonance [1] both experimentally and theoretically. We treat the interaction in terms of a regularized δ-function pseudopotential and consider the general case of particles with different trap frequencies, where the usual approach [2] of separating center-of-mass motion and relative motion fails. We numerically obtain the energy spectrum and the eigenfunctions from an exact diagonalization of the Hamiltonian. We find significant corrections to the energy not only due to the anharmonicity of the lattice site but also due to the different trap frequencies. Furthermore we calculate the transfer efficiency of the rf association and the lifetime of the molecules and compare our results with the experimental data. Finally we extend our study to other mixtures, such as 6Li and 133Cs, where the effect is even larger.
[1] C. Ospelkaus et al., Phys. Rev. Lett. 97, 120402 (2006).
[2] Th. Busch, B. G. Englert, K. Rzazewski, M. Wilkens, Found. Phys. 28, 549 (1998).