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Main Authors: Sakamoto, Daisuke, Naito, Soshun, Mori, Yusei, Mitarai, Kosuke
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.12697
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author Sakamoto, Daisuke
Naito, Soshun
Mori, Yusei
Mitarai, Kosuke
author_facet Sakamoto, Daisuke
Naito, Soshun
Mori, Yusei
Mitarai, Kosuke
contents Quantum circuit equivalence checking asks whether two circuits implement the same unitary. It guarantees compiler correctness and safe optimization, yet most existing approaches scale exponentially with the number of qubits or the circuit depth, or are restricted to specific circuit structures. In this work, we present an equivalence-checking method for circuits formed by arbitrary single-qubit layers interleaved with Clifford layers. This pattern is common in variational quantum algorithms and Hamiltonian simulation via Trotter decomposition. It can also represent any unitary with sufficient depth. We prove the existence of an efficient classical algorithm that determines whether a pair of circuits with shared single-qubit layers are equivalent for every possible choice of the shared single-qubit unitaries. The same algorithm can also certify their non-equivalence for fixed assignments of single-qubit unitaries. Our framework supports the validation of emerging quantum compilers and facilitate the discovery of novel circuit optimization passes.
format Preprint
id arxiv_https___arxiv_org_abs_2603_12697
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Efficient equivalence checking of Clifford-U circuits with shared single-qubit unitaries
Sakamoto, Daisuke
Naito, Soshun
Mori, Yusei
Mitarai, Kosuke
Quantum Physics
Quantum circuit equivalence checking asks whether two circuits implement the same unitary. It guarantees compiler correctness and safe optimization, yet most existing approaches scale exponentially with the number of qubits or the circuit depth, or are restricted to specific circuit structures. In this work, we present an equivalence-checking method for circuits formed by arbitrary single-qubit layers interleaved with Clifford layers. This pattern is common in variational quantum algorithms and Hamiltonian simulation via Trotter decomposition. It can also represent any unitary with sufficient depth. We prove the existence of an efficient classical algorithm that determines whether a pair of circuits with shared single-qubit layers are equivalent for every possible choice of the shared single-qubit unitaries. The same algorithm can also certify their non-equivalence for fixed assignments of single-qubit unitaries. Our framework supports the validation of emerging quantum compilers and facilitate the discovery of novel circuit optimization passes.
title Efficient equivalence checking of Clifford-U circuits with shared single-qubit unitaries
topic Quantum Physics
url https://arxiv.org/abs/2603.12697