FM 22-05; cond-mat/0507686

Authors: Giuseppe Benfatto, Alessandro Giuliani, Vieri Mastropietro

Title Fermi liquid behavior in the 2D Hubbard model at low temperatures

Abstract: We prove that the weak coupling 2D Hubbard model away from half filling is a Landau Fermi liquid up to exponentially small temperatures. In particular we show that the wave function renormalization is an order 1 constant and essentially temperature independent in the considered range of temperatures and that the interacting Fermi surface is a regular convex curve. This result is obtained by deriving a convergent expansion (which is not a power series) for the two point Schwinger function by Renormalization Group methods and proving at each order suitable power counting improvements due to the convexity of the interacting Fermi surface. Convergence follows from determinant bounds for the fermionic expectations.

Key words:  Hubbard model, Renormalization group, Fermi liquid

Giuseppe Benfatto
Matematica, Universita' di Roma 2
V.le della Ricerca Scientifica
00133 Roma, Italia
tel +39-06-7259-4698

em: benfatto@mat.uniroma2.it

Alessandro Giuliani
Physics, Princeton University
80544 Princeton, New Jersey, USA
tel +1-609-258-4369

em: giuliani@princeton.edu

Vieri Mastropietro
Matematica, Universita' di Roma 2
V.le della Ricerca Scientifica
00133 Roma, Italia
tel +39-06-7259-4209

em: mastropi@mat.uniroma2.it
http://ipparco.roma1.infn.it