Reversal of quantised Hall drifts at non-interacting and interacting topological boundaries

Abstract

The transport properties of gapless edge modes at boundaries between topologically distinct domains are of fundamental and technological importance. Therefore, it is crucial to gain a better understanding of topological edge states and their response to interparticle interactions. Here, we experimentally study long-distance quantised Hall drifts in a harmonically confined topological pump of non-interacting and interacting ultracold fermionic atoms. We find that quantised drifts halt and reverse their direction when the atoms reach a critical slope of the confining potential, revealing the presence of a topological boundary. The drift reversal corresponds to a band transfer between a band with Chern number $C=+1$ and a band with $C=-1$ via a gapless edge mode, in agreement with the bulk-edge correspondence for non-interacting particles. We establish that a non-zero repulsive Hubbard interaction leads to the emergence of an additional edge in the system, relying on a purely interaction-induced mechanism, in which pairs of fermions are split.

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Cited by in corpus (11)

• Interactions enable Thouless pumping in a nonsliding lattice
• Thouless pumping and trapping of two-component gap solitons
• Quantized Hall drift in a frequency-encoded photonic Chern insulator
• Chiral polaron formation on the edge of topological quantum matter
• Splitting and connecting singlets in atomic quantum circuits
• Topological photon pumping in quantum optical systems
• Reentrant topology and reverse pumping in a quasiperiodic flux ladder
• Galilei covariance of the theory of Thouless pumps
• Ultracold atomic lattice systems for simulating topological phases: A review
• Dark solitons in nonlinear Su-Schrieffer-Heeger lattices
• Optical control of electrons in a Floquet topological insulator