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Q: Fachverband Quantenoptik und Photonik

Q 35: Quantum Gases (Fermions) II

Q 35.7: Vortrag

Dienstag, 6. März 2018, 15:30–15:45, K 1.022

1D fermionic Floquet topological insulators with Hubbard interaction — •Haixin Qiu¹ and Johann Kroha^1,2 — ¹Physikalisches Institut and Bethe Center for Theoretical Physics, Universität Bonn, Nussallee 12, 53115 Bonn, Germany — ²Center for Correlated Matter, Zhejiang University, Hangzhou, Zhejiang 310058, China

The fermionic Rice-Mele model is a standard model for quantum ratchet transport in periodically driven, one-dimensional, bipartite chains. In the adiabatic limit, this model exhibits quantized transport (Thouless pump), while in the limit of fast drive quasistatic approximations with effective hopping parameters are possible. Here we study the Rice-Mele model with periodic drive of both, the hopping amplitudes and the onsite energy modulation,in the intermediate regime where the driving frequency is comparable to intrinsic energy scales. In this regime, topological Floquet-Bloch bands are possible because of an effectively two-dimensional Brillouin zone comprised of the periodic k-space and the periodic, continuous time space. We investigate the stability of the topological phase with respect to inelastic interactions. To that end, we include a Hubbard onsite repulsion U in the Floquet Hamiltonian of the Rice-Mele model. The Floquet space is truncated with up to ± 5 Floquet bands. We develop the Keldysh-Floquet Green’s function method for stationary non-equilibrium, which is non-trivial already in the non-interacting case because of the bipartite lattice structure. The Hubbard interaction is treated by 2nd-order selfconsistent perturbation theory in U. We present results for the Floquet spectral densities and the transport current.