Pritzker School of Molecular Engineering
Published August 21, 2020 | Version v1
Journal article Open

Bias-preserving gates with stabilized cat qubits

Creators

  • 1. Yale University
  • 2. Universit'e de Sherbrooke
  • 3. University of Waterloo
  • 4. University of Chicago

Description

The code capacity threshold for error correction using biased-noise qubits is known to be higher than with qubits without such structured noise. However, realistic circuit-level noise severely restricts these improvements. This is because gate operations, such as a controlled-NOT (CX) gate, which do not commute with the dominant error, unbias the noise channel. Here, we overcome the challenge of implementing a bias-preserving CX gate using biased-noise stabilized cat qubits in driven nonlinear oscillators. This continuous-variable gate relies on nontrivial phase space topology of the cat states. Furthermore, by following a scheme for concatenated error correction, we show that the availability of bias-preserving CX gates with moderately sized cats improves a rigorous lower bound on the fault-tolerant threshold by a factor of two and decreases the overhead in logical Clifford operations by a factor of five. Our results open a path toward high-threshold, low-overhead, fault-tolerant codes tailored to biased-noise cat qubits.

Data availability

All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors.

Files

sciadv.aay5901.pdf

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Additional details

Identifiers

DOI
10.1126/sciadv.aay5901
Other
oai:uchicago.tind.io:11047

Funding

National Science Foundation
DMR-1609326
Canada First
Research Excellence Fund
NSERC
United States Army Research Office
W911NF-18-1-0212
United States Army Research Office
W911NF-14-1-0098
Que ́bec-Nature et technologies
Fonds de Recherche
United States Army Research Office
W911NF-14-1-0103

UChicago Information

Division(s)
Pritzker School of Molecular Engineering