Lambert, Colin and Hagston, W. E. (1984) *New approach to perturbation theory of many-particle systems.* International Journal of Theoretical Physics, 23 (2). pp. 99-124. ISSN 0020-7748

## Abstract

We derive an infinite hierarchy of integral equations for the Green functions of a many-particle system. This set of equations forms the basis of a unified approach to the perturbation theory of many boson and many fermion systems and avoids the introduction of the adiabatic hypothesis. It is demonstrated how a well-known ground state perturbation theory of a system of interacting fermions is obtained without introducing disconnected diagrams. It is shown that the formalism allows a self-consistent determination of the condensate Green function of a condensed Bose system and a derivation of the Beliaev, Hugenholtz, and Pines result for the single-particle k 0 Green function is given. A new self-consistent equation for the k = 0 Green function is solved to yield the well-known self-energy relation 11 – 02 =which plays the role of a self-consistency condition on the theory.

Item Type: | Article |
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Journal or Publication Title: | International Journal of Theoretical Physics |

Subjects: | ?? qc ?? |

Departments: | Faculty of Science and Technology > Physics |

ID Code: | 58061 |

Deposited By: | ep_importer_pure |

Deposited On: | 22 Oct 2012 11:38 |

Refereed?: | Yes |

Published?: | Published |

Last Modified: | 30 Aug 2017 13:42 |

Identification Number: | |

URI: | http://eprints.lancs.ac.uk/id/eprint/58061 |

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