Impact of control signal phase noise on qubit fidelity

Impact of control signal phase noise on qubit fidelity | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Impact of control signal phase noise on qubit fidelity Agata Barsotti, Paolo Marconcini, Gregorio Procissi, Massimo Macucci This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9150191/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract As qubit decoherence times are increased and readout technologies are improved, nonidealities in the drive signals, such as phase noise, are going to represent a crucial limitation to the fidelity achievable at the end of complex control pulse sequences. Although the effect of phase noise of reference oscillators on qubit performance has been studied previously, its interaction with realistic time-dependent control pulses and its contribution to fidelity degradation has not yet been investigated in sufficient detail, and remains a critical challenge. Here we study the impact on fidelity of phase noise affecting reference oscillators with the help of numerical simulations, which allow us to directly take into account the interaction between the phase fluctuations in the control signals and the evolution of the qubit state, thereby achieving a comprehensive understanding of the actual role played by the different spectral components of phase noise. In particular, we perform an analysis of the effect of the individual noise frequency contributions, providing a clear identification of the spectral regions that most critically impact fidelity and establishing their relative weight in the overall fidelity degradation. Our method is based on the generation of phase noise realizations consistent with a given power spectral density, that are then applied to the pulse carrier in simulations, with Qiskit-Dynamics, of the qubit temporal evolution. By comparing the final state obtained at the end of a noisy pulse sequence with that in the ideal case and averaging over multiple noise realizations, we estimate the resulting degradation in fidelity, and, exploiting an approximate analytical representation of a carrier affected by phase fluctuations, we shed new light on the nature of the different contributions, and provide an intuitive physical picture. phase noise superconducting qubits control electronics fidelity Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 13 Apr, 2026 Reviews received at journal 13 Apr, 2026 Reviews received at journal 10 Apr, 2026 Reviewers agreed at journal 01 Apr, 2026 Reviewers agreed at journal 31 Mar, 2026 Reviewers agreed at journal 30 Mar, 2026 Reviewers invited by journal 20 Mar, 2026 Editor assigned by journal 19 Mar, 2026 Submission checks completed at journal 19 Mar, 2026 First submitted to journal 17 Mar, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9150191","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":610290900,"identity":"ab76ab35-7027-44c1-959f-2b2714cef416","order_by":0,"name":"Agata Barsotti","email":"data:image/png;base64,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","orcid":"","institution":"University of Pisa","correspondingAuthor":true,"prefix":"","firstName":"Agata","middleName":"","lastName":"Barsotti","suffix":""},{"id":610290903,"identity":"810a2df7-b766-48aa-8e9a-898e1d2a53cf","order_by":1,"name":"Paolo Marconcini","email":"","orcid":"","institution":"University of Pisa","correspondingAuthor":false,"prefix":"","firstName":"Paolo","middleName":"","lastName":"Marconcini","suffix":""},{"id":610290904,"identity":"4a0db4cb-bad7-447b-9590-2bf9d21bed14","order_by":2,"name":"Gregorio Procissi","email":"","orcid":"","institution":"University of Pisa","correspondingAuthor":false,"prefix":"","firstName":"Gregorio","middleName":"","lastName":"Procissi","suffix":""},{"id":610290905,"identity":"3e285887-5d9a-44c6-980e-63ad7fbb38b0","order_by":3,"name":"Massimo Macucci","email":"","orcid":"","institution":"University of Pisa","correspondingAuthor":false,"prefix":"","firstName":"Massimo","middleName":"","lastName":"Macucci","suffix":""}],"badges":[],"createdAt":"2026-03-17 14:53:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9150191/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9150191/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105564797,"identity":"5485bd29-8d22-49ee-818a-88d4725512d3","added_by":"auto","created_at":"2026-03-27 12:50:52","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4219985,"visible":true,"origin":"","legend":"","description":"","filename":"paperImpactphasenoisev1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9150191/v1_covered_d7116224-2f35-47bc-8929-e998fab000a3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of control signal phase noise on qubit fidelity","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"epj-quantum-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"epjq","sideBox":"Learn more about [EPJ Quantum Technology](http://epjquantumtechnology.springeropen.com)","snPcode":"40507","submissionUrl":"https://submission.nature.com/new-submission/40507/3","title":"EPJ Quantum Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"phase noise, superconducting qubits, control electronics, fidelity","lastPublishedDoi":"10.21203/rs.3.rs-9150191/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9150191/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAs qubit decoherence times are increased and readout technologies are improved, nonidealities in the drive signals, such as phase noise, are going to represent a crucial limitation to the fidelity achievable at the end of complex control pulse sequences. Although the effect of phase noise of reference oscillators on qubit performance has been studied previously, its interaction with realistic time-dependent control pulses and its contribution to fidelity degradation has not yet been investigated in sufficient detail, and remains a critical challenge. Here we study the impact on fidelity of phase noise affecting reference oscillators with the help of numerical simulations, which allow us to directly take into account the interaction between the phase fluctuations in the control signals and the evolution of the qubit state, thereby achieving a comprehensive understanding of the actual role played by the different spectral components of phase noise. In particular, we perform an analysis of the effect of the individual noise frequency contributions, providing a clear identification of the spectral regions that most critically impact fidelity and establishing their relative weight in the overall fidelity degradation. Our method is based on the generation of phase noise realizations consistent with a given power spectral density, that are then applied to the pulse carrier in simulations, with Qiskit-Dynamics, of the qubit temporal evolution. By comparing the final state obtained at the end of a noisy pulse sequence with that in the ideal case and averaging over multiple noise realizations, we estimate the resulting degradation in fidelity, and, exploiting an approximate analytical representation of a carrier affected by phase fluctuations, we shed new light on the nature of the different contributions, and provide an intuitive physical picture.\u003c/p\u003e","manuscriptTitle":"Impact of control signal phase noise on qubit fidelity","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-25 10:19:13","doi":"10.21203/rs.3.rs-9150191/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-13T13:21:07+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-13T08:43:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-10T09:43:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"12901867661569671057826730471044724894","date":"2026-04-02T01:01:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"24785944545565766917626882787451835777","date":"2026-04-01T01:46:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"216098773775980488091614659041039071936","date":"2026-03-31T03:37:13+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-20T13:40:35+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-20T03:55:43+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-20T03:55:19+00:00","index":"","fulltext":""},{"type":"submitted","content":"EPJ Quantum Technology","date":"2026-03-17T14:37:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"epj-quantum-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"epjq","sideBox":"Learn more about [EPJ Quantum Technology](http://epjquantumtechnology.springeropen.com)","snPcode":"40507","submissionUrl":"https://submission.nature.com/new-submission/40507/3","title":"EPJ Quantum Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c07808c0-ad1c-447a-9b00-58c991b5a885","owner":[],"postedDate":"March 25th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-11T19:23:31+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-25 10:19:13","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9150191","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9150191","identity":"rs-9150191","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}