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arXiv · 1112.3584

1/f noise of Josephson-junction-embedded microwave resonators at single photon energies and millikelvin temperatures

K. W. Murch·S. J. Weber·E. M. Levenson-Falk·R. Vijay·I. Siddiqi
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Abstract

We present measurements of 1/f frequency noise in both linear and Josephson-junction-embedded superconducting aluminum resonators in the low power, low temperature regime - typical operating conditions for superconducting qubits. The addition of the Josephson junction does not result in additional frequency noise, thereby placing an upper limit for fractional critical current fluctuations of $10^{-8}$ (Hz$^{-1/2}$) at 1 Hz for sub-micron, shadow evaporated junctions. These values imply a minimum dephasing time for a superconducting qubit due to critical current noise of 40 -- 1400 $\mu$s depending on qubit architecture. Occasionally, at temperatures above 50 mK, we observe the activation of individual fluctuators which increase the level of noise significantly and exhibit Lorentzian spectra.

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K. W. Murch, S. J. Weber, E. M. Levenson-Falk, R. Vijay, I. Siddiqi. 2011-12-15. 1/f noise of Josephson-junction-embedded microwave resonators at single photon energies and millikelvin temperatures. https://doi.org/10.1063/1.3700964

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