{"paper":{"title":"Precision Spectroscopy of Atomic Hydrogen and Variations of Fundamental Constants","license":"","headline":"","cross_cats":[],"primary_cat":"physics.atom-ph","authors_text":"A. Clairon, C. Salomon, F. Pereira Dos Santos, G. Santarelli, H. Marion, I. Maksimovic, J. Gr\\\"unert, M. Abgrall, M. Fischer, M. Zimmermann, N.Kolachevsky, P. Laurent, P. Lemonde, R. Holzwarth, S. Bize, Th. Udem, T.W. H\\\"ansch","submitted_at":"2003-11-26T13:33:31Z","abstract_excerpt":"In 2003 we have measured the absolute frequency of the $(1S, F=1, m_F=\\pm 1) \\leftrightarrow (2S, F'=1, m_F'=\\pm 1)$ two-photon transition in atomic hydrogen. We observed a variation of $(-29\\pm 57)$ Hz over a 44 months interval separating this measurement from the previous one performed in 1999. We have combined this result with recently published results of optical transition frequency measurement in the $^{199}$Hg$^+$ ion and and comparison between clocks based on $^{87}$Rb and $^{133}$Cs. From this combination we deduce the stringent limits for fractional time variation of the fine structu"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"physics/0311128","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"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"}