|Title||Topological edge states with ultracold atoms carrying orbital angular momentum in a diamond chain|
|Publication Type||Journal Article|
|Year of Publication||2019|
|Authors||Pelegrí, G, Marques, AM, Dias, RG, Daley, AJ, Ahufinger, V, Mompart, J|
|Journal||Phys. Rev. A|
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.