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Bibliographic Details
Main Authors: Skaras, Timothy, Ginsparg, Paul
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2505.08069
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author Skaras, Timothy
Ginsparg, Paul
author_facet Skaras, Timothy
Ginsparg, Paul
contents We present an algorithm for performing quantum process tomography on an unknown $n$-qubit unitary $C$ from the Clifford group. Our algorithm uses Bell basis measurements to deterministically learn $C$ with $4n + 3$ queries, which is the asymptotically optimal query complexity. In contrast to previous algorithms that required access to $C^\dagger$ to achieve optimal query complexity, our algorithm achieves the same performance without querying $C^\dagger$. Additionally, we show the algorithm is robust to perturbations and can efficiently learn the closest Clifford to an unknown non-Clifford unitary $U$ using query overhead that is logarithmic in the number of qubits.
format Preprint
id arxiv_https___arxiv_org_abs_2505_08069
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Process Tomography for Clifford Unitaries
Skaras, Timothy
Ginsparg, Paul
Quantum Physics
We present an algorithm for performing quantum process tomography on an unknown $n$-qubit unitary $C$ from the Clifford group. Our algorithm uses Bell basis measurements to deterministically learn $C$ with $4n + 3$ queries, which is the asymptotically optimal query complexity. In contrast to previous algorithms that required access to $C^\dagger$ to achieve optimal query complexity, our algorithm achieves the same performance without querying $C^\dagger$. Additionally, we show the algorithm is robust to perturbations and can efficiently learn the closest Clifford to an unknown non-Clifford unitary $U$ using query overhead that is logarithmic in the number of qubits.
title Process Tomography for Clifford Unitaries
topic Quantum Physics
url https://arxiv.org/abs/2505.08069