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QI: Fachverband Quanteninformation
QI 25: Materials and Devices for Quantum Technology II (joint session HL/QI)
QI 25.2: Talk
Thursday, March 21, 2024, 14:30–14:45, EW 203
Light-matter correlations in Quantum Floquet Engineering — •Beatriz Pérez-González1, Gloria Platero1, and Álvaro Gómez-León2 — 1Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Madrid, Spanien — 2Instituto de Física Fundamental (IFF-CSIC), Madrid, Spanien
Quantum Floquet engineering requires a proper gauge-invariant description of light-matter interaction to correctly capture the physics of the system beyond the strong-coupling regime. This means that such models typically involve a highly non-linear dependence on the photonic operators which makes their analysis and simulation complex.
In this talk, we present a non-perturbative truncation scheme for the light-matter Hamiltonian, which is valid for arbitrary coupling strength. This method can successfully capture the physics of both, fermions and photons, in agreement with the predictions of gauge-invariant models. Importantly, it also keeps track of the role of light-matter correlations, which are essential to correctly predict the properties of the many-body system.
We find that, even in the high-frequency regime, light-matter correlations can spontaneously break key symmetries. We focus on the implications this has when the electronic system has topological properties, since the breaking of a certain symmetry can jeopardize topological properties and their robustness. We exemplify our findings with the SSH chain, and show that a topological phase transition can be induced by coupling to a cavity and that the critical point can be predicted from the spectral function.
Keywords: topological systems; quantum optics; light-matter interactions; topological edge states; cavity QED