The Attractive Hubbard Model in 2D: Is it capable of describing a pseudogap and preformed pairs?
| dc.creator | Letz, M. | |
| dc.date | 1998-07-29 | |
| dc.date.accessioned | 2026-07-07T03:11:10Z | |
| dc.date.available | 2026-07-07T03:11:10Z | |
| dc.description | Deviations from Fermi liquid behavior are well documented in the normal state of the cuprate superconductors, and some of these differences seem to be related to pre-transitional features appearing at temperatures above T$_c$. The observation of a pseudogap, e.g. in ARPES experiments, is a familiar example of this physics. One potential explanation for this behaviour involves preformed pairs with finite lifetimes existing in the normal state above T$_c$. In this way two characteristic temperatures can be established. A higher one T$^*$ at which pairs begin to form and the actual T$_c$ at which a phase-coherent superconducting phase is established. In order to test these ideas we have investigated the negative U Hubbard model in two dimensions in the fully self-consistent ladder approximation at low electron densities. In the non self-consistent version of this theory the system always shows an instability towards Bose-condensation of infinite lifetime pairs. In contrast to this, pairs obtain a finite lifetime due to pair-pair interaction and the sharp two-particle bound state is strongly lifetime broadened when self-consistency is applied. A quasi-particle scattering rate which varies linearly with temperature is also found. The fully self-consistent calculation we were able to perform using a ${\bf {\vec k}}$--averaged approximation in which the self-energy loses its ${\bf {\vec k}}$-dispersion due to a ${\bf {\vec k}}$-average. This approximation is found to preserve the essential physics. | |
| dc.description | 3 pages, 1 figure, prepared for the proceedings of the euroconference "Polarons, Condensation, ..." in Erice, Sicilia, June 1998 | |
| dc.identifier | https://arxiv.org/abs/cond-mat/9807383 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/9807383 | |
| dc.identifier | J. of Supercond. 12 (1), 61, (1999) | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/28471 | |
| dc.subject | Strongly Correlated Electrons | |
| dc.subject | Superconductivity | |
| dc.title | The Attractive Hubbard Model in 2D: Is it capable of describing a pseudogap and preformed pairs? | |
| dc.type | text |