Multiphoton spectroscopy of a hybrid quantum system
Pavel A. Bushev, Clemens Müller, Jürgen Lisenfeld, Jared H. Cole, Alexander V. Lukashenko, Alexander Shnirman, Alexey Vladimirovich Ustinov · Physical Review B · 2010
We report on experimental multiphoton spectroscopy of a hybrid quantum system consisting of a superconducting phase qubit coherently coupled to an intrinsic two-level system (TLS). We directly probe hybridized states of the combined qubit-TLS system in the strongly interacting regime, where both the qubit-TLS coupling and the driving cannot be considered as weak perturbations. This regime is described by a theoretical model which incorporates anharmonic corrections, multiphoton processes and decoherence. We present a detailed comparison between experiment and theory and find excellent agreement over a wide range of parameters.