# Analog quantum simulation of the Rabi model in the ultra-strong coupling regime

Braumüller, Jochen; Marthaler, Michael; Schneider, Andre; Stehli, Alexander; Rotzinger, Hannes; Weides, Martin; Ustinov, Alexey V.

Abstract:
The quantum Rabi model describes the fundamental mechanism of light-matter interaction. It consists of a two-level atom or qubit coupled to a quantized harmonic mode via a transversal interaction. In the weak coupling regime, it reduces to the well-known Jaynes–Cummings model by applying a rotating wave approximation. The rotating wave approximation breaks down in the ultra-strong coupling regime, where the effective coupling strength $g$ is comparable to the energy ω of the bosonic mode, and remarkable features in the system dynamics are revealed. Here we demonstrate an analog quantum simulation of an effective quantum Rabi model in the ultra-strong coupling regime, achieving a relative coupling ratio of $g$/ω ~ 0.6. The quantum hardware of the simulator is a superconducting circuit embedded in a cQED setup. We observe fast and periodic quantum state collapses and revivals of the initial qubit state, being the most distinct signature of the synthesized model.

 Zugehörige Institution(en) am KIT Institut für Theoretische Festkörperphysik (TFP)Physikalisches Institut (PHI) Publikationstyp Zeitschriftenaufsatz Jahr 2017 Sprache Englisch Identifikator ISSN: 2041-1723 URN: urn:nbn:de:swb:90-756910 KITopen-ID: 1000075691 Erschienen in Nature Communications Band 8 Heft 1 Seiten Art. Nr. 779 Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds Nachgewiesen in Web of ScienceScopus
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