Cutting circuits with multiple two-qubit unitaries

Lukas Schmitt; Christophe Piveteau; David Sutter

doi:10.22331/q-2025-02-18-1634

Cutting circuits with multiple two-qubit unitaries

Lukas Schmitt^1,2, Christophe Piveteau¹, and David Sutter²

¹Institute for Theoretical Physics, ETH ZurichIBM Quantum
²IBM Research Europe – Zurich

Published:	2025-02-18, volume 9, page 1634
Editor:	Xin Wang
Eprint:	arXiv:2312.11638v4
Doi:	https://doi.org/10.22331/q-2025-02-18-1634
Citation:	Quantum 9, 1634 (2025).

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Abstract

Quasiprobabilistic cutting techniques allow us to partition large quantum circuits into smaller subcircuits by replacing non-local gates with probabilistic mixtures of local gates. The cost of this method is a sampling overhead that scales exponentially in the number of cuts. It is crucial to determine the minimal cost for gate cutting and to understand whether allowing for classical communication between subcircuits can improve the sampling overhead. In this work, we derive a closed formula for the optimal sampling overhead for cutting an arbitrary number of two-qubit unitaries and provide the corresponding decomposition. We find that cutting several arbitrary two-qubit unitaries together is cheaper than cutting them individually and classical communication does not give any advantage.

Featured image: Two different cutting scenarios (parallel and black box cuts), where the dashed line represents the cut. The unitaries $U_{i}$ are arbitrary two-qubit gates acting on A and B. In the black box setting E and F denote arbitrary
quantum channels.

Popular summary

Suppose we want to run a circuit consisting of 1,000 qubits, but we only have 200-qubit devices available. The theory of circuit cutting allows us to partition large quantum circuits into smaller subcircuits. By performing appropriate classical post-processing, the expectation value of the original large circuit can be retrieved. The cost is a simulation overhead that scales exponentially with the number of cut gates. In this work, we derive the optimal sampling overhead for arbitrary two-qubit gates.

► BibTeX data

@article{Schmitt2025cuttingcircuits,
  doi = {10.22331/q-2025-02-18-1634},
  url = {https://doi.org/10.22331/q-2025-02-18-1634},
  title = {Cutting circuits with multiple two-qubit unitaries},
  author = {Schmitt, Lukas and Piveteau, Christophe and Sutter, David},
  journal = {{Quantum}},
  issn = {2521-327X},
  publisher = {{Verein zur F{\"{o}}rderung des Open Access Publizierens in den Quantenwissenschaften}},
  volume = {9},
  pages = {1634},
  month = feb,
  year = {2025}
}

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[4] Laura S. Herzog, Lukas Burgholzer, Christian Ufrecht, Daniel D. Scherer, and Robert Wille, 2025 62nd ACM/IEEE Design Automation Conference (DAC) 1 (2025) ISBN:979-8-3315-0304-8.

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The above citations are from Crossref's cited-by service (last updated successfully 2026-08-09 21:02:24) and SAO/NASA ADS (last updated successfully 2026-08-09 21:02:26). The list may be incomplete as not all publishers provide suitable and complete citation data.

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