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.
Show all persons

Published in

npj Quantum Information

20566387 (eISSN)

Vol. 9 Issue 1 art. no 26

Research Project(s)

Wallenberg Centre for Quantum Technology (WACQT)

Knut and Alice Wallenberg Foundation (KAW 2017.0449, KAW2021.0009, KAW2022.0006), 2018-01-01 -- 2030-03-31.

Categorizing

Subject Categories (SSIF 2011)

Atom and Molecular Physics and Optics

Other Physics Topics

Signal Processing

Condensed Matter Physics

Identifiers

DOI

10.1038/s41534-023-00689-6

More information

Latest update

1/14/2025