Driven Topology

Novel time-dependent topological phases realized in cold-atom quantum simulators

July 13, 2020

An international team of physicists from the Ludwig-Maximilians Universität (LMU) and the Max Planck Institute of Quantum Optics together with collaborators from the University of Cambridge, TU Berlin and the Université Libre de Bruxelles succeeded in realizing a novel genuine time-dependent topological system with ultracold atoms in periodically-driven optical honeycomb lattices.

Topological energy bands can be realized in engineered quantum system via periodic driving. Their topological properties transcend those of undriven settings and can be characterized by winding numbers, which now have been revealed in a cold atom experiment.

Topological phases of matter have attracted a lot of interest due to their unique electronic properties that often result in exotic surface or boundary modes, whose existence is rooted in the non-trivial topological properties of the underlying system. In particular, the robustness of these properties makes them interesting for applications. In order to gain more insight into the rich physics of topological phases of matter, numerous examples have been engineered in well-controlled synthetic quantum systems. In this context, periodic driving has emerged as an important technique to emulate the physics of undriven topological solid-state systems. The properties of driven topological systems, however, transcend those of their static counterparts. Now scientists at LMU have succeeded in generating such a time-dependent topological system with ultracold atoms in periodically-driven optical lattices. Moreover, they have directly studied the modified bulk-edge correspondence, which predicts the presence of edge modes, even though conventional topological invariants fail to reveal them. The study appeared online in the scientific magazine “Nature Physics” on June 29, 2020.

This is a short version. The original article is published on the homepage of the excellence clusters MCQST under https://www.mcqst.de/news-and-events/news/driven-topology.html

(Source: LMU)

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