Restricted Randomized Benchmarking with Universal Gates of Fixed Sequence Length

TL;DR

This paper presents a resource-efficient randomized benchmarking protocol that uses a fixed-length universal gate set to generate Haar-randomness, simplifying implementation and improving noise modeling for small quantum systems.

Contribution

It introduces a novel RB protocol using fixed-length universal gates to generate Haar-randomness without complex operations or t-designs, enhancing practicality for small qubit systems.

Findings

Protocol effectively creates Haar-randomness with fixed-length gates.

Benchmarking shows accurate fidelity estimation compared to standard RB.

Noise analysis indicates potential for improved experimental noise modeling.

Abstract

The standard randomized benchmarking protocol requires access to often complex operations that are not always directly accessible. Compiler optimization does not always ensure equal sequence length of the directly accessible universal gates for each random operation. We introduce a version of the RB protocol that creates Haar-randomness using a directly accessible universal gate set of equal sequence length rather than relying upon a t-design or even an approximate one. This makes our protocol highly resource efficient and practical for small qubit numbers. We exemplify our protocol for creating Haar-randomness in the case of single and two qubits. Benchmarking our result with the standard RB protocol, allows us to calculate the overestimation of the average gate fidelity as compared to the standard technique. We augment our findings with a noise analysis which demonstrates that our method could be an effective tool for building accurate models of experimental noise.