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Journal of Physics Conference Series

Spectroscopy of the modes of a non-linear superconducting microwave resonator via inter-mode coupling and bifurcation amplification

Giovanna Tancredi, Grégoire Ithier, P. J. Meeson

Published Dec 8, 2014• 0 citations
Publisher

Abstract

The Josephson non-linearity provides a route to high sensitivity measurements through the bifurcation of a resonant mode into two metastable dynamical states. We probe the bifurcation regime of a superconducting microwave co-planar resonator incorporating a controlled non-linearity made of an array of SQUIDs. The switching probability between metastable states may be determined by repeated measurements under nominally identical conditions. We show that measurements of this probability and the inter-mode coupling introduced by the SQUIDs may be used for spectroscopy of other resonant modes. We also find the width of the switching-curve is within a factor two of quantitative agreement with Dykman's model, but that the switching probability is affected by a low frequency noise that has its source on-chip.

DOI
10.1088/1742-6596/568/5/052022

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We performed a novel phase-sensitive microwave reflection experiment which directly probes the dynamics of the Josephson plasma resonance in both the linear and the nonlinear regime. When the junction was driven below the plasma frequency into the nonlinear regime, we observed for the first time the transition between two different dynamical states predicted for nonlinear systems. In our experiment, this transition appears as an abrupt change in the reflected signal phase at a critical excitation power. This controlled dynamical switching can form the basis of a sensitive amplifier, in particular, for the readout of superconducting qubits.
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