Mainz 2017 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 53: Poster: Quantum Optics and Photonics III
Q 53.15: Poster
Thursday, March 9, 2017, 17:00–19:00, P OG2
Creating topological interfaces and detecting chiral edge modes in a two-dimensional optical lattice — •Frederik Görg1, Nathan Goldman2, Gregor Jotzu1, Michael Messer1, Kilian Sandholzer1, Rémi Desbuquois1, and Tilman Esslinger1 — 1Institute for Quantum Electronics, ETH Zurich, Zurich, Switzerland — 2CENOLI, Université Libre de Bruxelles, Brussels, Belgium
The appearance of topological properties in lattice systems caused by a non-trivial topological band structure in the bulk is closely related to the existence of chiral edge modes via the bulk-edge correspondence. These edge states appear at the interface of two spatial regions with a distinct topology, which for example naturally arise at the boundaries of a sample surrounded by vacuum. In cold atom systems, these edge modes are difficult to detect, since the underlying harmonic trapping potential does not feature sharp boundaries. Therefore, we propose a different method to design topological interfaces within the bulk of the system. We illustrate this scheme by an optical lattice realization of the Haldane model, where a spatially varying lattice beam leads to the appearance of distinct topological phases in separated regions of space. The versatility of the method allows to tune the position, the localization length and the chirality of the edge modes. We numerically study the propagation of wave packets in such a system and demonstrate the feasibility to experimentally detect chiral edge states. Finally, we show that the edge modes, unlike the bulk states, are topologically protected against the effects of disorder, which makes a random potential a powerful tool to detect edge states in cold atom setups.