SAMOP 2023 – scientific programme

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QI: Fachverband Quanteninformation

QI 6: Poster I (joint session QI/Q)

QI 6.33: Poster

Monday, March 6, 2023, 16:30–19:00, Empore Lichthof

Quantisation and breakdown of topological transport in the Hubbard-Thouless pump — •Marius Gächter, Zijie Zhu, Anne-Sophie Walter, Konrad Viebahn, Stephan Roschinski, Joaquín Minguzzi, Kilian Sandholzer, and Tilman Esslinger — ETH, Zurich, Switzerland

Predicting the fate of topologically protected transport in the strongly correlated regime represents a central challenge within condensed matter physics. On the one hand, free-fermion energy bands and their geometric properties give rise to quantised transport phenomena, such as the quantum Hall effect and its dynamic analogon, the Thouless pump. The quantisation in these systems is considered robust against perturbations that commute with a protecting symmetry. On the other hand, interparticle interactions support strongly correlated states of matter, which often preclude particle transport, exemplified by the Mott transition in the Hubbard model. Will topology prevail in the presence of strong correlations? Here, we systematically probe the response of a topological Thouless pump to Hubbard interactions in an ultracold-atom experiment. We identify three distinct regimes, that is, pair pumping for strongly attractive interactions, quantised pumping for weak and moderate interactions, as well as the breakdown of transport for strong repulsive Hubbard U. Our experiments pave the way for investigating edge effects in interacting topological insulators, as well as interaction-induced topological phases with no counterpart in free-fermion systems.