arXiv:2609.35547 · v2

Sublinear Copies Suffice for Fidelity Estimation with Pauli Measurements

首次提交 2026-09-29 00:24

版本更新 2026-11-04 21:00

雷达观测 2026-11-05 11:10

摘要

We present the first worst-case, sublinear protocol to estimate the fidelity between a known target state and unknown lab-prepared state using Pauli basis measurements. More precisely, for $d$-dimensional states, we estimate the fidelity to $\pm \varepsilon$ using $o(d^{0.9675})/\varepsilon^2$ copies, which applies to all target states. Furthermore, our results establish improved guarantees for Pauli shadow tomography and Distributed Inner Product Estimation.

作者备注：Added references to shadow tomography, improved exponent using depolarizing channel identities