Generalization of the Hartree-Fock-Bogoliubov theory: one and two quasiparticle excitations
| dc.creator | Tommasini, Paolo | |
| dc.creator | de Passos, E. J. V. | |
| dc.creator | Pires, M. O. C. | |
| dc.creator | Piza, A. F. R. de Toledo | |
| dc.date | 2003-07-30 | |
| dc.date.accessioned | 2026-07-07T02:52:40Z | |
| dc.date.available | 2026-07-07T02:52:40Z | |
| dc.description | We present a generalization of the Hartree-Fock Bogoliubov (HFB) theory in which the coupling between one and two quasi-particles is taken into account.This is done by writing the excitation operators as linear combinations of one and two HFB quasi-particles. The excitation energies and the quasi-particle amplitudes are given by generalized Bogoliubov equations. The excitation spectrum has two branches. The first one is a discrete branch which is gapless and has a phonon character at large wave-length and, contrarily to HFB, is always stable. This branch is detached from a continuum branch whose threshold, at fixed total momentum, coincides with the two quasi-particle threshold of the HFB theory. The gap between these two branches at P=0 is equal to two times the HFB gap, which then provides for the relevant energy scale. We also give numerical results for a specific case. | |
| dc.description | 27 pages, 3 figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0307745 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0307745 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/21926 | |
| dc.subject | Soft Condensed Matter | |
| dc.title | Generalization of the Hartree-Fock-Bogoliubov theory: one and two quasiparticle excitations | |
| dc.type | text |