Ultra-broadband microwave travelling-wave parametric amplifier for qubit readout

ORAL

Abstract

Superconducting parametric amplifiers (paramps) have been used to demonstrate qubit readout approaching the quantum limit in the gigahertz regime. A common limitation of these amplifiers has been relatively small bandwidth due to the use of a resonant nonlinearity. We present measurements of a novel type of paramp based on a superconducting non-linear transmission line. Due to the absence of a resonant structure, these devices achieve useful gain with instantaneous bandwidth approaching 4 GHz. We present detailed measurements of amplifier performance metrics and scattering parameters. Additionally, we have coupled this amplifier to a 3D transmon qubit both directly and via an isolator for comparison. We discuss qubit coherence times and readout performance. This type of amplifier is a strong candidate for an ultra-low-noise following amplifier in frequency-multiplexed qubit readout schemes.

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Authors

  • Chris Macklin

    • QNL, UC Berkeley

  • D.H. Slichter

    • NIST - Boulder

  • O. Yaakobi

    • INRS-EMT, 1650 Boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 Canada

  • L. Friedland

    • Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel

  • V. Bolkhovsky

    • MIT Lincoln Laboratory, Lexington, MA, USA

  • D.A. Braje

    • MIT Lincoln Laboratory, Lexington, MA, USA

  • G. Fitch

    • MIT Lincoln Laboratory, Lexington, MA, USA

  • W.D. Oliver

    • MIT Lincoln Laboratory, Lexington, MA, USA

  • I. Sidiqi

    • QNL, UC Berkeley