FM 03-16; arXiv:1605.07407

Authors: Alessandro Giuliani, Ian Jauslin, Vieri Mastropietro, Marcello Porta

Title: Topological phase transitions and universality in the Haldane-Hubbard model

Sommario: We study the Haldane-Hubbard model by exact Renormalization Group techniques. We construct the topological phase diagram, for weak interactions. We predict that many-body interactions induce a shift of the transition line. The presence of new intermediate phases, absent in the non interacting case, is rigorously excluded at weak coupling. Despite the nontrivial renormalization of the wave function and of the Fermi velocity, the conductivity is universal: at the renormalized critical line, both the discontinuity of the transverse conductivity and the longitudinal conductivity do not depend on the interaction, thanks to remarkable cancellations due to lattice Ward Identities.

Alessandro Giuliani
Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, 00146 Roma Italy
giuliani@mat.uniroma3.it

Ian Jauslin
University of Zurich, Mathematics Department, Winterthurerstrasse 190, 8057 Zurich, Switzerland
ian.jauslin@math.uzh.ch

Vieri Mastropietro
Dipartimento di Matematica, Università degli Studi di Milano, 20133 Milano Italy
vieri.mastropietro@unimi.it

Marcello Porta
University of Zurich, Mathematics Department, Winterthurerstrasse 190, 8057 Zurich, Switzerland
marcello.porta@math.uzh.ch