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

TL;DR

This paper explores how ultracold atoms with orbital angular momentum in a diamond lattice create topological edge states and exhibit phenomena like Aharonov-Bohm caging, combining analytical and numerical methods.

Contribution

It introduces a novel approach to induce topological phases using OAM states in a diamond chain, revealing protected edge states and interference effects.

Findings

Topologically non-trivial band structure with protected edge states

Induction of effective $\pi$ flux through basis rotations

Observation of Aharonov-Bohm caging phenomena

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 $\pi$ flux through the plaquettes and give rise to a topologically non-trivial band structure and protected edge states. 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.