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arXiv · 1006.2161

Exact results on the two-particle Green's function of a Bose-Einstein condensate

Takafumi Kita
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Abstract

Starting from the Dyson-Beliaev and generalized Gross-Pitaevskii equations with an extra nonlocal potential, we derive an exact expression of the two-particle Green's function K for an interacting Bose-Einstein condensate in terms of unambiguously defined self-energies and vertices. The formula can be a convenient basis for approximate calculations of K. It also tells us that poles of K are not shared with (i.e. shifted from) those of the single-particle Green's function, contrary to the conclusion of previous studies.

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Takafumi Kita. 2010-06-10. Exact results on the two-particle Green's function of a Bose-Einstein condensate. https://doi.org/10.1103/physrevb.81.214513

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