Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Coherence-limited digital control of a superconducting qubit using a Josephson pulse generator at 3 K

Published

Author(s)

Manuel Castellanos Beltran, Adam Sirois, Logan Howe, David Olaya, John Biesecker, Samuel P. Benz, Pete Hopkins

Abstract

Compared to traditional semiconductor control electronics (TSCE) located at room temperature, cryogenic single flux quantum (SFQ) electronics can provide qubit measurement and control alternatives that address critical issues related to scalability of cryogenic quantum processors. Single-qubit control and readout have been demonstrated recently using SFQ circuits coupled to superconducting qubits. Experiments where the SFQ electronics are co-located with the qubit have suffered from excess decoherence and loss due to quasiparticle poisoning of the qubit. A previous experiment by our group showed that moving the control electronics to the 3 K stage of the dilution refrigerator avoided this source of decoherence in a high-coherence three-dimensional transmon geometry. In this paper, we also generate the pulses at the 3 K stage but have optimized the qubit design and control lines for scalable two-dimensional transmon devices. We directly compare the qubit lifetime T1,, coherence time T∗2, and gate fidelity when the qubit is controlled by the Josephson pulse generator (JPG) circuit vs the TSCE setup. We find agreement within the daily fluctuations for T1 and T∗2⁠, and agreement within 10% for randomized benchmarking. We also performed interleaved randomized benchmarking on individual JPG gates demonstrating an average error per gate of 0.46% showing good agreement with what is expected based on the qubit coherence and higher-state leakage. These results are an order of magnitude improvement in gate fidelity over our previous work and demonstrate that a Josephson microwave source operated at 3 K is a promising component for scalable qubit control.
Citation
Applied Physics Letters
Volume
122
Issue
19

Keywords

Quantum computing, scalable, cryogenic control, Josephson junction (JJ), Single Flux Quantum (SFQ), transmon, superconductor

Citation

Castellanos Beltran, M. , Sirois, A. , Howe, L. , Olaya, D. , Biesecker, J. , Benz, S. and Hopkins, P. (2023), Coherence-limited digital control of a superconducting qubit using a Josephson pulse generator at 3 K, Applied Physics Letters, [online], https://doi.org/10.1063/5.0147692, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936240 (Accessed June 25, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created May 8, 2023, Updated August 14, 2023