1/N-Expansion and the Dilute Bose Gas Beyond Mean-field Theory

Jens O. Andersen

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1/N-Expansion and the Dilute Bose Gas Beyond Mean-field Theory

Jens O. Andersen

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Abstract

We consider the nonrelativistic interacting Bose gas at zero and finite temperature. Using the 1/N-expansion, we derive expressions for the free energy density and the number density to next-to-leading order in 1/N. Outside the critical region and at weak coupling, our calculations reduce to the well-known mean-field results for the dilute Bose gas. We also rederive the nonperturbative critical density for Bose condensation which was first calculated by Baym, Blaizot, Holzmann, Lalöe, and Vautherin.

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Jens O. Andersen. 2006-08-11. 1/N-Expansion and the Dilute Bose Gas Beyond Mean-field Theory. https://arxiv.org/abs/cond-mat/0608265

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