Dresden 2020 – wissenschaftliches Programm
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TT 12.7: Vortrag
Montag, 16. März 2020, 16:30–16:45, HSZ 103
Fractional corner charges in a 2D super-lattice Bose-Hubbard model — •Julian Bibo1,4, Izabella Lovas1,4, Yizhi You3, Fabian Grusdt1,2,4,5, and Frank Pollmann1,4 — 1Technische Universität München — 2Ludwig-Maximilians-Universität München — 3Princeton Center for Theoretical Science — 4Munich Center for Quantum Science and Technology — 5Department of Physics and Institute for Advanced Study, Technical University of Munich
Higher order topological insulators (HOTIs) represent a novel class of topological phases protected by a combination of spatial and internal symmetries. While many non-interacting system have been introduced and studied, it is unclear to which extend the results obtained in non-interacting systems transfer to their strongly-interacting counter parts. In our work, we introduce an experimentally accessible model, a 2D super-lattice Bose-Hubbard model on a square lattice at half-filling, that realizes a robust higher order topological phase protected by charge conservation and fourfold rotation symmetry. Excitingly, our model predicts the presence of symmetry protected fractional charges e/2 to occur at the corners. The presence and robustness of the predicted fractional corner charges is confirmed using the Density Renormalisation Group Ansatz (DMRG). Finally, we propose a way to measure the characteristic fractional corner charges and also provide simulations for the measurement.