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Nonlinear resonant behavior of the dispersive readout scheme for a superconducting flux qubit

Janice C. Lee·William D. Oliver·Karl K. Berggren·T. P. Orlando
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Abstract

A nonlinear resonant circuit comprising a SQUID magnetometer and a parallel capacitor is studied as a readout scheme for a persistent-current (PC) qubit. The flux state of the qubit is detected as a change in the Josephson inductance of the SQUID magnetometer, which in turn mediates a shift in the resonance frequency of the readout circuit. The nonlinearity and resulting hysteresis in the resonant behavior are characterized as a function of the power of both the input drive and the associated resonance peak response. Numerical simulations based on a phenomenological circuit model are presented which display the features of the observed nonlinearity.

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Janice C. Lee, William D. Oliver, Karl K. Berggren, T. P. Orlando. 2006-09-22. Nonlinear resonant behavior of the dispersive readout scheme for a superconducting flux qubit. https://doi.org/10.1103/physrevb.75.144505

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