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arXiv · cond-mat/0310697

Best mean-field for condensates

L. S. Cederbaum·A. I. Streltsov
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Abstract

The Gross-Pitaevskii equation assumes that all (identical) bosons of a condensate reside in a single one-particle function. Here, we raise the question whether it always provides the best mean-field ansatz for condensates, leading to the lowest mean-field ground state energy. To this end, we derive a mean-field approach allowing for bosons to reside in several different one-particle functions. The number of bosons in each of these functions is a variational parameter minimizing the energy. The energy and one-particle functions at these optimal numbers can be determined directly. A numerical example is presented demonstrating that the mean-field energy of trapped bosons can be below that provided by the Gross-Pitaevskii equation. Implications are discussed.

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L. S. Cederbaum, A. I. Streltsov. 2003-10-29. Best mean-field for condensates. https://doi.org/10.1016/j.physleta.2003.09.058

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