{"paper":{"title":"Absolute frequency measurement of the $^{176}$Lu$^+\\,(^{3}\\mathrm{D}_1)$ standard against the NRC-FCs2 fountain with $2.6\\times10^{-16}$ uncertainty","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["quant-ph"],"primary_cat":"physics.atom-ph","authors_text":"Bin Jian, K. J. Arnold, M. D. Barrett, M. D. K. Lee, N. Jayjong, Qin Qichen, Qi Zhao, Scott Beattie, Zhao Zhang","submitted_at":"2026-07-08T06:21:14Z","abstract_excerpt":"We report an improved absolute frequency measurement of the $^{176}$Lu$^+\\,(^{3}\\mathrm{D}_1)$ optical frequency standard, evaluated via a remote link to the NRC-FCs2 caesium fountain primary frequency standard. Operating a single ion clock with 94.2% uptime over 10 days, and using an ambiguity-resolved precise point positioning (PPP-AR) link over the Global Positioning System (GPS), we determine an absolute frequency of $353\\,638\\,794\\,073\\,800.33(9)\\,$Hz at a fractional uncertainty of $2.6 \\times 10^{-16}$. This agrees with our previous result, which underpins the CIPM recommended frequency "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2607.07044","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2607.07044/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}