Impact of decoherence on the fidelity of quantum gates leaving the computational subspace

The fidelity of quantum operations is often limited by incoherent errors, which typically can be modeled by fundamental Markovian noise processes such as amplitude damping and dephasing. In Phys. Rev. Lett. 129, 150504 (2022), we presented an analytical result for the average gate fidelity of a gene...

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Main Authors: Tahereh Abad, Yoni Schattner, Anton Frisk Kockum, Göran Johansson
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2025-04-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2025-04-03-1684/pdf/
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author Tahereh Abad
Yoni Schattner
Anton Frisk Kockum
Göran Johansson
author_facet Tahereh Abad
Yoni Schattner
Anton Frisk Kockum
Göran Johansson
author_sort Tahereh Abad
collection DOAJ
description The fidelity of quantum operations is often limited by incoherent errors, which typically can be modeled by fundamental Markovian noise processes such as amplitude damping and dephasing. In Phys. Rev. Lett. 129, 150504 (2022), we presented an analytical result for the average gate fidelity of a general multiqubit operation in terms of the dissipative rates and the corresponding Lindblad jump operators, provided that the operation remains in the computational subspace throughout the time evolution. Here we generalize this expression for the average gate fidelity to include the cases where the system state temporarily leaves the computational subspace during the gate. Such gate mechanisms are integral to several quantum-computing platforms, and our formula is applicable to all of them; as examples, we employ it for the two-qubit controlled-Z gate in both superconducting qubits and neutral atoms. We also obtain the average gate fidelity for simultaneous operations applied in multiqubit systems. These results are useful for understanding the error budgets of quantum gates while scaling up quantum computers.
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publisher Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
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spelling doaj-art-cfa6144e2fb64a6facb5aa894eb4c3ad2025-08-20T03:16:57ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2025-04-019168410.22331/q-2025-04-03-168410.22331/q-2025-04-03-1684Impact of decoherence on the fidelity of quantum gates leaving the computational subspaceTahereh AbadYoni SchattnerAnton Frisk KockumGöran JohanssonThe fidelity of quantum operations is often limited by incoherent errors, which typically can be modeled by fundamental Markovian noise processes such as amplitude damping and dephasing. In Phys. Rev. Lett. 129, 150504 (2022), we presented an analytical result for the average gate fidelity of a general multiqubit operation in terms of the dissipative rates and the corresponding Lindblad jump operators, provided that the operation remains in the computational subspace throughout the time evolution. Here we generalize this expression for the average gate fidelity to include the cases where the system state temporarily leaves the computational subspace during the gate. Such gate mechanisms are integral to several quantum-computing platforms, and our formula is applicable to all of them; as examples, we employ it for the two-qubit controlled-Z gate in both superconducting qubits and neutral atoms. We also obtain the average gate fidelity for simultaneous operations applied in multiqubit systems. These results are useful for understanding the error budgets of quantum gates while scaling up quantum computers.https://quantum-journal.org/papers/q-2025-04-03-1684/pdf/
spellingShingle Tahereh Abad
Yoni Schattner
Anton Frisk Kockum
Göran Johansson
Impact of decoherence on the fidelity of quantum gates leaving the computational subspace
Quantum
title Impact of decoherence on the fidelity of quantum gates leaving the computational subspace
title_full Impact of decoherence on the fidelity of quantum gates leaving the computational subspace
title_fullStr Impact of decoherence on the fidelity of quantum gates leaving the computational subspace
title_full_unstemmed Impact of decoherence on the fidelity of quantum gates leaving the computational subspace
title_short Impact of decoherence on the fidelity of quantum gates leaving the computational subspace
title_sort impact of decoherence on the fidelity of quantum gates leaving the computational subspace
url https://quantum-journal.org/papers/q-2025-04-03-1684/pdf/
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