FM 1-2011 (arXiv:1101.2169)

Authors: Alessandro Giuliani, Vieri Mastropietro, Marcello Porta

Title: Universality of conductivity in interacting graphene
 
Abstract: The Hubbard model on the honeycomb lattice describes charge carriers in graphene with short range interactions. While the interaction modifies several physical quantities, like the value of the Fermi velocity or the wave function renormalization, the a.c. conductivity has a universal value independent of the microscopic details of the model: there are no interaction corrections, provided that the interaction is weak enough and that the system is at half filling. We give a rigorous proof of this fact, based on exact Ward Identities and on constructive Renormalization Group methods.

Keywords: graphene, conductivity, Ward identities, renormalization group

Alessandro Giuliani
Dipartimento di Matematica
Università di Roma Tre
L.go S. Leonardo Murialdo 1, 00146 Roma - Italy
e-mail: giuliani AT mat DOT uniroma3 DOT it

Vieri Mastropietro
Dipartimento di Matematica
Università di Roma Tor Vergata
V.le della Ricerca Scientifica 1, 00133 Roma - Italy
e-mail: mastropi AT mat DOT uniroma2 DOT it

Marcello Porta
Dipartimento di Fisica
Università di Roma Sapienza
P.le A. Moro, 00185 Roma - Italy
e-mail: marcello DOT porta AT roma1 DOT infn DOT it