Planar extrapolation of the correlation problem that permits pairing

Authors
Foerster, D
Citation
D. Foerster, Planar extrapolation of the correlation problem that permits pairing, PHYS REV B, 62(20), 2000, pp. 13376-13382
Citations number
19
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B
ISSN journal
01631829 → ACNP
Volume
62
Issue
20
Year of publication
2000
Pages
13376 - 13382
Database
ISI
SICI code
0163-1829(20001115)62:20<13376:PEOTCP>2.0.ZU;2-I
Abstract
It was observed previously that the SU(N) extension of the Hubbard model is dominated by planar diagrams at large N, but the possibility of supercondu cting pairing got lost in this extrapolation. To allow for pairing, we repl ace SU(N) by U(N,q), the unitary group in a vector space of quaternions. At the level of the free energy, the difference between the SU(N) and U(N,q) extrapolations appears only to first nonleading order in N.