München 2004 – scientific programme

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Q: Quantenoptik und Photonik

Q 28: Quantengase III

Q 28.8: Talk

Tuesday, March 23, 2004, 18:15–18:30, HS 225

Ground-state energy and depletion of a two-component dilute Bose gas beyond the Gross-Pitaevskii approximation — •André Eckardt, Christoph Weiss, and Martin Holthaus — Institut für Physik, Carl von Ossietzky Universität, D-26111 Oldenburg

The ground state of a homogeneous, weakly interacting two-component Bose gas is studied. The Bogoliubov approach is employed to determine ground-state energy and depletion. Using a recently developed method [1] for avoiding all spurious divergent terms, the treatment becomes particularly transparent. The analytical results simplyfy considerably if the masses of both species are equal. It is stressed that the standard Bogoliubov treatment presupposes not only the low-density regime, but also interaction potentials such that the replacement of the exact s-wave scattering length by its lowest Born approximation is adequate.

[1] C. Weiss, M. Block, D. Boers, A. Eckardt, and M. Holthaus; Ground-state energy of a weakly interacting Bose gas: Calculation without regularization; preprint (Universität Oldenburg, 2003)