A central problem in the theory of strongly correlated fermion systems, concerns the nature of their low-lying excitations. It is generally accepted that, except for special cases with symmetry breaking, three dimensional (3D) interacting Fermi systems, are well described in terms of weakly correlated quasi-particles with quantum numbers in one-toone correspondence with those identifying the excitations of a non-interacting Fermi gas. This is the basic assumption underlying the Landau theory of Fermi liquids (FL), which was originally proposed as a phenomenological description of strongly interacting fermions by Landau in early 1956[1), an then established microscopically by Nozieres and Luttinger in 1962[2]. Quite a different scenario occurs in lD interacting Fermi systems. Apart from specific models developing gaps in the excitation spectrum, most fermion systems in one dimension with repulsive interactions, do have low-lying gapless excitations, like ordinary Fermi liquids, but totally different from the quasi-particles predicted by Landau theory. The low-energy behavior of most of these lD interacting fermion systems with gapless linear excitations, can be understood in terms of few model dependent constants, which parametrize all the long-wavelength properties...
New results for interacting Fermi systems: the 2D Hubbard model at low density and the two coupled chain problem / Fabrizio, Michele. - (1992 Nov 02).
Autori: | |
Autori: | Fabrizio, Michele |
Titolo: | New results for interacting Fermi systems: the 2D Hubbard model at low density and the two coupled chain problem |
Relatore/i interni: | |
Data di pubblicazione: | 2-nov-1992 |
Appare nelle tipologie: | 8.1 PhD thesis |
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1963_5392_PhD_Fabrizio_Michele.pdf | Tesi | Non specificato | Open Access Visualizza/Apri |