High fidelity single-shot readout of a transmon qubit using a SLUG μwave amplifier

  1. Yanbing Liu,
  2. Srikanth Srinivasan,
  3. D. Hover,
  4. Shaojiang Zhu,
  5. R. McDermott,
  6. and A. A. Houck
We report high-fidelity, quantum nondemolition, single-shot readout of a superconducting transmon qubit using a DC-biased superconducting low-inductance undulatory galvanometer(SLUG) amplifier. The SLUG improves the system signal-to-noise ratio by 7 dB in a 20 MHz window compared with a bare HEMT amplifier. An optimal cavity drive pulse is chosen using a genetic search algorithm, leading to a maximum combined readout and preparation fidelity of 91.9% with a measurement time of Tmeas = 200ns. Using post-selection to remove preparation errors caused by heating, we realize a combined preparation and readout fidelity of 94.3%.
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