Topological edge states with ultracold atoms carrying orbital angular momentum in a diamond chain

TitleTopological edge states with ultracold atoms carrying orbital angular momentum in a diamond chain
Publication TypeJournal Article
Year of Publication2019
AuthorsPelegrí, G, Marques, AM, Dias, RG, Daley, AJ, Ahufinger, V, Mompart, J
JournalPhys. Rev. A
Volume99
Pagination023612
Date PublishedFeb
Abstract

We study the single-particle properties of a system formed by ultracold atoms loaded into the manifold of l=1 orbital angular momentum (OAM) states of an optical lattice with a diamond-chain geometry. Through a series of successive basis rotations, we show that the OAM degree of freedom induces phases in some tunneling amplitudes of the tight-binding model that are equivalent to a net π flux through the plaquettes. These effects give rise to a topologically nontrivial band structure and protected edge states which persist everywhere in the parameter space of the model, indicating the absence of a topological transition. By taking advantage of these analytical mappings, we also show that this system constitutes a realization of a square-root topological insulator. In addition, we demonstrate that quantum interferences between the different tunneling processes involved in the dynamics may lead to Aharanov-Bohm caging in the system. All these analytical results are confirmed by exact diagonalization numerical calculations.

URLhttps://link.aps.org/doi/10.1103/PhysRevA.99.023612
DOI10.1103/PhysRevA.99.023612
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