Process Tomography for Clifford Unitaries

• URL: http://arxiv.org/abs/2505.08069v1
• Date: Mon, 12 May 2025 21:11:04 GMT
• Title: Process Tomography for Clifford Unitaries
• Authors: Timothy Skaras, Paul Ginsparg,
• Abstract summary: We present an algorithm for performing quantum process tomography on an unknown $n$-qubit unitary $C$.<n>Our algorithm achieves the same performance without querying $Cdagger$.
• Score: 0.276240219662896
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: 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.

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