Regensburg 2022 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 34: Correlated Electrons: Theory 2
TT 34.10: Talk
Thursday, September 8, 2022, 17:30–17:45, H23
Splitting of topological charge pumping in an interacting two-component fermionic Rice-Mele Hubbard model — •Eric Bertok1, Fabian Heidrich-Meisner1, and Armando A. Aligia2 — 1Institute for Theoretical Physics, Georg-August-Universität Göttingen — 2Centro Atómico Bariloche and Instituto Balseiro, Bariloche, Argentina
A Thouless pump transports an integer amount of charge when pumping adiabatically around a singularity. We study the splitting of such a critical point into two separate critical points by adding a Hubbard interaction. Furthermore, we consider extensions to a spinful Rice-Mele model, namely a staggered magnetic field or an Ising-type spin coupling, further reducing the spin symmetry. The resulting models additionally allow for the transport of a single charge in a two-component system of spinful fermions, whereas in the absence of interactions, zero or two charges are pumped. In the SU(2)-symmetric case, the ionic Hubbard model is visited once along pump cycles that enclose a single singularity. Adding a staggered magnetic field additionally transports an integer amount of spin while the Ising term realizes a pure charge pump. We employ real-time simulations in finite and infinite systems to calculate the adiabatic charge and spin transport, complemented by the analysis of gaps and the many-body polarization to confirm the adiabatic nature of the pump. The resulting charge pumps are expected to be measurable in finite-pumping speed experiments in ultra-cold atomic gases. We discuss the implications of our results for a related quantum-gas experiment by Walter et al. [arXiv:2204.06561].