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Q: Fachverband Quantenoptik und Photonik
Q 9: Quantum gases (Bosons) I
Q 9.2: Vortrag
Montag, 9. März 2020, 14:30–14:45, e214
Anomalous Floquet topological phases in periodically-driven hexagonal lattices — •Karen Wintersperger1,2, Christoph Braun1,2,3, Immanuel Bloch1,2,3, and Monika Aidelsburger1,2 — 1Ludwig-Maximilians-Universität, Schellingstraße 4, 80799 München — 2Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München — 3Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching
Ultracold atoms in periodically-driven optical lattices can be used to simulate systems with nontrivial topological properties. Due to the periodic driving, energy conservation is relaxed which makes it possible to realize systems with properties that go beyond those of conventional static systems. For instance, chiral edge modes can exist even if the bulk is topologically trivial [1].
We study such anomalous Floquet phases experimentally using a BEC of K39 in an optical honeycomb lattice with periodically modulated tunnel couplings. By monitoring the closing and reopening of energy gaps in the band structure we are able to track the transitions between different Floquet phases. Moreover, we probe the topological porperties of the bulk by measuring the Hall deflection induced by local changes in the Berry curvature. Combining these measurements enables us to extract the topological invariants of the bulk bands and the energy gaps, which are both required to accurately classify the topological phases of Floquet systems [2, 3].
[1] T. Kitagawa et al., Phys. Rev. B 82, 235114 (2010) [2] M. Rudner et al., PRX 3, 031005 (2013) [3] N. Ünal et al., PRL 122, 253601 (2019)