Interaction-induced charge pumping in a topological many-body system

Thouless charge pumps are a dynamical 1+1 dimensional variant of the Quantum Hall effect, with a quantized transport of charge in an adiabatic and periodic process. Ultracold atoms in optical lattices allow the realization of this setup and a number of experiments investigated the case of noninteracting atoms. Here, we report on the a joint experimental-theory study of interaction-induced pumping in a two-component Rice-Mele Hubbard model [1]. The key idea is to use a pump cycle whose origin is shifted in the parameter space spanned by staggered potential and dimerizationalong the direction of the staggered potential, different from the usual origin-centered cycles [2]. This shifted cycle captures the effect of Hubbard interactions on the singularities in parameter space [3]. A near-quantized pumping of one atom per cycle is observed in the first pump cycle, which does not occur in the absence of interactions in this model. The talk will focus on the theoretical results obtained from numerical simulations that account for realistic conditions of the experiment. We are also able to explain the breakdown of pumping after the first cycle due to spin-charge coupling in this model and discuss ways to stabilize the pump for many pumping cycles.

[1] Viebahn et al., arXiv:2308.03756

[2] Walter et al., Nature Phys. 2023, https://doi.org/10.1038/s41567-023-02145-w

[3] Bertok, Heidrich-Meisner, Aligia, Phys. Rev. B 106, 045141 (2022)