A near-quantum-limited diamond maser amplifier operating at millikelvin temperatures

A near-quantum-limited diamond maser amplifier operating at millikelvin temperatures | 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 Physical Sciences - Article A near-quantum-limited diamond maser amplifier operating at millikelvin temperatures Yuimaru Kubo, Morihiro Ohta, Ching-Ping Lee, Vincent Sietses, and 9 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6766240/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract The tremendous progress in detecting tiny microwave signals from quantum devices under test at millikelvin temperatures has been enabled by superconducting parametric amplifiers [1–4], owing to their near-quantum-limited noise performance [5, 6]. Another fundamentally distinct approach could be offered by masers, the microwave counterpart of lasers, which have long been predicted to exhibit quantum-limited noise performance when operated in the absence of thermal noise and with sufficient population inversion [7–11]. Here, we demonstrate the first-ever non-superconducting, near-quantumlimited microwave amplifier operating at millikelvin temperatures based on a maser utilising impurity spins in diamond. We achieve power gains exceeding 30 dB, a minimum noise temperature of 0.86 K (corresponding to 2.2 noise photons), and a maximum 1 dB output compression point of −63 dBm at 6.595 GHz. The observed noise temperature is on par with superconducting parametric amplifiers, while the compression points exceed those of Josephson travellingwave parametric amplifiers by 20 to 30 dB. By revisiting masers at millikelvin temperatures, our work reestablishes them as robust low-noise amplifiers for emerging quantum technologies, including quantum computing, magnetic resonance spectroscopy [12, 13], and fundamental physics [14–16]. Physical sciences/Physics/Quantum physics/Quantum information Physical sciences/Physics/Quantum physics/Quantum metrology Full Text Additional Declarations There is NO Competing Interest. Supplementary Files Supplementary.pdf Supplementary information for "A near-quantum-limited diamond maser amplifier operating at millikelvin temperatures" Cite Share Download PDF Status: Under Review Version 1 posted 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. 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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-6766240","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":465390108,"identity":"71fb87d9-2e72-4cb0-a105-a6d73556d765","order_by":0,"name":"Yuimaru 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