Transmon qubit readout fidelity at the threshold for quantum error correction without a quantum-limited amplifier
Journal article, 2023
High-fidelity and rapid readout of a qubit state is key to quantum computing and communication, and it is a prerequisite for quantum error correction. We present a readout scheme for superconducting qubits that combines two microwave techniques: applying a shelving technique to the qubit that reduces the contribution of decay error during readout, and a two-tone excitation of the readout resonator to distinguish among qubit populations in higher energy levels. Using a machine-learning algorithm to post-process the two-tone measurement results further improves the qubit-state assignment fidelity. We perform single-shot frequency-multiplexed qubit readout, with a 140 ns readout time, and demonstrate 99.5% assignment fidelity for two-state readout and 96.9% for three-state readout–without using a quantum-limited amplifier.
Author
Liangyu Chen
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Hangxi Li
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Yong Lu
University of Stuttgart
Christopher Warren
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Christian Krizan
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Sandoko Kosen
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Marcus Rommel
Chalmers, Microtechnology and Nanoscience (MC2), Nanofabrication Laboratory
Shahnawaz Ahmed
Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics
Amr Osman
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Janka Biznárová
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Anita Fadavi Roudsari
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Benjamin Lienhard
Princeton University
Marco Caputo
Technical Research Centre of Finland (VTT)
K. Grigoras
Technical Research Centre of Finland (VTT)
L. Gronberg
Technical Research Centre of Finland (VTT)
J. Govenius
Technical Research Centre of Finland (VTT)
Anton Frisk Kockum
Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics
Per Delsing
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Jonas Bylander
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Giovanna Tancredi
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
npj Quantum Information
20566387 (eISSN)
Vol. 9 1 26Wallenberg Centre for Quantum Technology (WACQT)
Knut and Alice Wallenberg Foundation (KAW 2017.0449, KAW2021.0009, KAW2022.0006), 2018-01-01 -- 2030-03-31.
Subject Categories (SSIF 2011)
Atom and Molecular Physics and Optics
Other Physics Topics
Signal Processing
Condensed Matter Physics
DOI
10.1038/s41534-023-00689-6