Simulation-free fidelity estimation of universal quantum processors via output order statistics of chaotic circuits
Phys. Rev. Applied 26, 024016 – Published 7 August, 2026
DOI: https://doi.org/10.1103/9c4r-9l6y
Abstract
We introduce a simulation-free approach to fidelity estimation in chaotic circuits implemented on universal quantum processors, based on the order statistics of measured output probabilities. The approach requires only the most frequently observed measurement outcomes and builds on analytical results for the order statistics of Haar-random quantum states derived here. Modeling noise via an effective depolarizing channel, we construct maximum-likelihood estimators that infer circuit fidelity from a small number of top-ranked outcomes, without requiring classical amplitude calculations. The method is benchmarked on publicly available data from Google’s 12-qubit Sycamore experiment and supported by numerical simulations, providing a framework for fidelity estimation in intermediate-scale quantum devices.
