Group Seminar via Zoom: Signatures and robustness of few-boson fractional Chern insulators and their excitations in finite Hofstadter-Hubbard lattices

December 21, 2021

André Eckardt, TU Berlin
Group meeting via video conference (Zoom)
Tuesday, December 21, 9:00 am (MEZ)

Due to the Covid-19 pandemic, we are still holding our group seminars and journal clubs via video conference.This procedure enables us to continue our research, enhance discussions and exchange important information.


The combination of artificial magnetic fields with strong repulsive interactions is predicted to give rise to bosonic fractional-chern-insulator (FCI) ground states in the Hofstadter-Hubbard model, corresponding to a nu=1/2 Laughlin state. We investigate measurable signatures of such a state in realistic lattices of about 10 particles with open boundary conditions, as they can be realized in quantum-gas microscopes and are favorable with respect to adiabatic state preparation. We study bulk incompressibility and chiral edge motion in the ground state and show that the fractional charge of the elementary quasiparticle and hole excitations can be probed either by using local pinning potentials or local flux insertion. We find signatures consistent with an FCI state for systems of linear extent of six and more sites, which are robust against the variation of various parameters, like the flux and the total particle number.

[1] B. Wang, F. N. Ünal, and A. Eckardt, Phys. Rev. Lett. 120, 243602 (2018)
[2] M. Raciunas, F.N. Ünal, E. Anisimovas, and A. Eckardt, Phys. Rev. A 98, 063621 (2018)
[3] B. Wang, X.-Y. Dong, A. Eckardt, arXiv:2111.011110

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