Benchmarking the performance of a high-Q cavity qudit using random unitaries

Journal Article · Mon Apr 14 00:00:00 EDT 2025 · Quantum Sci.Technol.

DOI:https://doi.org/10.1088/2058-9565/adc47c· OSTI ID:2440224

Bornman, Nicholas ^[1]; Roy, Tanay ^[1]; Job, Joshua A. ^[2]; Anand, Namit ^[3]; Perdue, Gabriel N. ^[1]; Zorzetti, Silvia ^[1]; Sohaib Alam, M. ^[4]

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1. Fermilab
2. Lockheed, Sunnyvale
3. NASA, Ames; Unlisted, US
4. NASA, Ames; Google Inc.

High-coherence cavity resonators are excellent resources for encoding quantum information in higher-dimensional Hilbert spaces, moving beyond traditional qubit-based platforms. A natural strategy is to use the Fock basis to encode information in qudits. One can perform quantum operations on the cavity mode qudit by coupling the system to a non-linear ancillary transmon qubit. However, the performance of the cavity-transmon device is limited by the noisy transmons. It is, therefore, important to develop practical benchmarking tools for these qudit systems in an algorithm-agnostic manner. We gauge the performance of these qudit platforms using sampling tests such as the heavy output generation test as well as the linear cross-entropy benchmark, by way of simulations of such a system subject to realistic dominant noise channels. We use selective number-dependent arbitrary phase and unconditional displacement gates as our universal gateset. Our results show that contemporary transmons comfortably enable controlling a few tens of Fock levels of a cavity mode. This framework allows benchmarking even higher dimensional qudits as those become accessible with improved transmons.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Google Inc.; Lockheed, Sunnyvale; NASA, Ames; Unlisted, US
• Sponsoring Organization: US Department of Energy
• Grant/Contract Number: 89243024CSC000002
• OSTI ID: 2440224
• Report Number(s): FERMILAB-PUB-24-0362-SQMS; arXiv:2408.13317; oai:inspirehep.net:2822958
• Journal Information: Quantum Sci.Technol., Journal Name: Quantum Sci.Technol. Journal Issue: 2 Vol. 10
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY