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TT: Fachverband Tiefe Temperaturen
TT 65: Poster Session Topological Topics
TT 65.28: Poster
Donnerstag, 19. März 2020, 15:00–19:00, P2/EG
Topological charge pumping under realistic conditions — •Eric Bertok1, Andrew Hayward1,2, and Fabian Heidrich-Meisner1 — 1Institut für Theoretische Physik, Göttingen — 2Arnold-Sommerfeld Center for Theoretical Physics, Munich
Recent experiments with ultra-cold atomic gases have realized topological charge pumps [1,2]. Non-adiabatic effects due to finite pumping speeds have already been studied via a Floquet analysis in the periodic system [3], but the combined effect of an external harmonic trap, a finite particle number, and these non-adiabatic effects due to a finite pump speed has not been considered. In our work, the interplay between these realistic aspects are explored and an interpretation of the mechanisms for topological charge pumping in a trapped system is developed. The full time-dependent Schroedinger equation is solved by exact diagonalization for the non-interacting system, and the dependence of the quantized particle transport on the pumping frequency and the trap strength is identified. Breakdowns from exact quantization due to excitations to the higher band are observed and are found to be highly dependent on the pumping frequency, with deviations for slow pumping and special pumping frequencies appearing at intermediate pumping times at which the pumping breaks down entirely.
This work was supported by the DFG (Deutsche Forschungsgemeinschaft) via Research Unit FOR2414.
[1] Lohse et al. Nature Phys 12, 350-354 (2016)
[2] Nakajima et al. Nature Phys 12, 296-300 (2016)
[3] Privitera et al. Phys. Rev. Lett. 120, 106601 (2018)