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Quantum spin Hall insulator interacting with quantum light: Inhomogeneous Dicke model
Author(s) -
Gulácsi Balázs,
Dóra Balázs
Publication year - 2016
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201600246
Subject(s) - physics , floquet theory , hamiltonian (control theory) , quantum mechanics , topological insulator , photon , quantum , condensed matter physics , integrable system , quantum spin hall effect , superradiance , quantum hall effect , quantum electrodynamics , magnetic field , mathematical physics , mathematical optimization , mathematics , nonlinear system , laser
Time‐periodic perturbations due to classical electromagnetic fields are useful to engineer the topological properties of matter using the Floquet theory. Here, we investigate the effect of quantized electromagnetic fields by focusing on the quantized light–matter interaction on the edge state of a quantum spin Hall insulator. We show that this interaction can be studied using an inhomogeneous Dicke model and that the corresponding Hamiltonian is integrable. A Dicke‐type superradiant phase transition occurs at arbitrary weak coupling and the electronic spectrum acquires a finite gap. In addition, when the total number of excitations are fixed, a photocurrent is generated along the edge, pseudoquantized as ω ln ω in the low‐frequency limit and decaying as 1 / ω for high frequencies with ω being the photon frequency.