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Title: High fidelity qubit readout with the superconducting low-inductance undulatory galvanometer microwave amplifier

We describe the high fidelity dispersive measurement of a superconducting qubit using a microwave amplifier based on the Superconducting Low-inductance Undulatory Galvanometer (SLUG). The SLUG preamplifier achieves gain of 19 dB and yields a signal-to-noise ratio improvement of 9 dB over a state-of-the-art HEMT amplifier. We demonstrate a separation fidelity of 99% at 700 ns compared to 59% with the HEMT alone. The SLUG displays a large dynamic range, with an input saturation power corresponding to 700 photons in the readout cavity.
Authors:
; ; ; ;  [1] ; ; ; ;  [2]
  1. Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)
  2. Department of Physics, University of California, Santa Barbara, California 93106 (United States)
Publication Date:
OSTI Identifier:
22262607
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 15; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALVANOMETERS; INDUCTANCE; MICROWAVE AMPLIFIERS; PHOTONS; QUBITS; SIGNAL-TO-NOISE RATIO