Winding number order in the Haldane model with interactions

10 págs.; 4 figs.; Open Access funded by Creative Commons Atribution Licence 3.0We study the Haldane model with nearest-neighbor interactions. This model is physically motivated by the associated implementation with ultracold atoms. We show that the topological phase of the interacting model can be characterized by a physically observable winding number. The robustness of this number extends well beyond the topological insulator phase towards attractive and repulsive interactions that are comparable to the kinetic energy scale of the model. We identify and characterize the relevant phases of the model as a function of the interaction strength. ©2016 IOP Publishing Ltd and Deutsche Physikalische GesellschaftThis work has been supported by EPSRC grant EP/I038683/1 and the Spanish MINECO Project FIS2012-33022 and CAM Research Network QUITEMAD+.Peer Reviewe