Exact results on the two-particle Green's function of a Bose-Einstein condensate
Quantum Gases
2014-11-21 v1 Statistical Mechanics
Superconductivity
Nuclear Theory
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.
Keywords
Cite
@article{arxiv.1006.2161,
title = {Exact results on the two-particle Green's function of a Bose-Einstein condensate},
author = {Takafumi Kita},
journal= {arXiv preprint arXiv:1006.2161},
year = {2014}
}
Comments
5 pages, 2 figures, to appear in Phys. Rev. B