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arXiv · 1207.6825

Large Dispersive Shift of Cavity Resonance Induced by a Superconducting Flux Qubit in the Straddling Regime

K. Inomata·T. Yamamoto·P. -M. Billangeon·Y. Nakamura·J. S. Tsai
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Abstract

We demonstrate enhancement of the dispersive frequency shift in a coplanar waveguide resonator induced by a capacitively-coupled superconducting flux qubit in the straddling regime. The magnitude of the observed shift, 80 MHz for the qubit-resonator detuning of 5 GHz, is quantitatively explained by the generalized Jaynes-Cummings model which takes into account the contribution of the qubit higher energy levels. By applying the enhanced dispersive shift to the qubit readout, we achieved 90% contrast of the Rabi oscillations which is mainly limited by the energy relaxation of the qubit.

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K. Inomata, T. Yamamoto, P. -M. Billangeon, Y. Nakamura, J. S. Tsai. 2012-07-30. Large Dispersive Shift of Cavity Resonance Induced by a Superconducting Flux Qubit in the Straddling Regime. https://doi.org/10.1103/physrevb.86.140508

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