Transmon qubit readout fidelity at the threshold for quantum error correction without a quantum-limited amplifier
Abstract
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 16, 2023
- Source ID
- 10.1038/s41534-023-00689-6
Entities
People
- Amr Osman
- Anita Fadavi Roudsari
- Anton Frisk Kockum
- Benjamin Lienhard
- Christian Križan
- Christopher Warren
- Giovanna Tancredi
- Hang-Xi Li
- Janka Biznárová
- Jonas Bylander
- Joonas Govenius
- Kestutis Grigoras
- Leif Grönberg
- Liangyu Chen
- Marco Caputo
- Marcus Rommel
- Per Delsing
- Sandoko Kosen
- Shahnawaz Ahmed
- Yong Lu
Organizations
- Army Research Office
- Carl-Zeiss-Stiftung
- European Science Foundation
- Horizon 2020
- Knut and Alice Wallenberg Foundation
- Research Council of Finland
- Swedish Research Council
- United States Department of Energy