Quantization and its breakdown in a Hubbard–Thouless pump


Date

2023-10

Publication Type

Journal Article

ETH Bibliography

yes

Citations

Altmetric

Data

Abstract

Geometric properties of wave functions can explain the appearance of topological invariants in many condensed-matter and quantum systems. For example, topological invariants describe the plateaux observed in the quantized Hall effect and the pumped charge in its dynamic analogue—the Thouless pump. However, the presence of interparticle interactions can affect the topology of a material, invalidating the idealized formulation in terms of Bloch waves. Despite pioneering experiments in different platforms, the study of topological matter under variations in interparticle interactions has proven challenging. Here we experimentally realize a topological Thouless pump with fully tuneable Hubbard interactions in an optical lattice and observe regimes with robust pumping, as well as an interaction-induced breakdown. We confirm the pump’s robustness against interactions that are smaller than the protecting gap for both repulsive and attractive interactions. Furthermore, we identify that bound pairs of fermions are responsible for quantized transport at strongly attractive interactions. However, for strong repulsive interactions, topological pumping breaks down, but we show how to reinstate it by modifying the pump trajectory. Our results will prove useful for further investigations of interacting topological matter, including edge effects and interaction-induced topological phases.

Publication status

published

Editor

Book title

Volume

9 (10)

Pages / Article No.

1471 - 1475

Publisher

Nature

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Topological matter; Ultracold gases

Organisational unit

03599 - Esslinger, Tilman / Esslinger, Tilman check_circle

Notes

Funding

182650 - Interplay between Topology, Interactions and Dissipation in Driven Quantum Many-Body Systems (SNF)
209376 - Adiabatically pumping topologically protected quantum many-body systems (AdiaPump) (SNF)
742579 - Mass, heat and spin transport in interlinked quantum gases (EC)

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