Authors: G. Benfatto, V. Mastropietro

Title: On the density-density critical indices in interacting Fermi systems.

Abstract: The behaviour of correlation functions of $d=1$ interacting fermionic systems is determined by a small number of critical indices. We prove that one of them is exactly zero. As a consequence, the behavior of the Fourier transform of the density-density correlation at zero momentum is qualitatively unaffected by the interaction, contrary to what happens at $\pm 2 \tilde p_F$, if $\tilde p_F$ is the Fermi momentum. The result is obtained by implementing Ward identities in a Renormalization Group approach.

Key words: Critical indices, Ward identities, spin chains.

G.Benfatto, V. Mastropietro

Universita' di Roma 2, Dip. Matematica

Via Fontanile di Carcaricola

00133 Roma, Italia