Winding number order in the Haldane model with interactions

TL;DR

This paper investigates the Haldane model with interactions, demonstrating that a physically observable winding number characterizes its topological phase and remains robust under various interaction strengths, revealing the model's phase structure.

Contribution

It introduces a physically observable winding number to characterize the topological phase in an interacting Haldane model, extending understanding beyond non-interacting cases.

Findings

Winding number remains robust with interactions

Identification of relevant phases in the model

Topological phase persists under strong interactions

Abstract

We study the Haldane model with nearest-neighbor interactions. This model is physically motivated by the associated ultracold atoms implementation. 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.