{"paper":{"title":"Ultra-stable laser with average fractional frequency drift rate below $5\\times10^{-19}/\\mathrm{s}$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["physics.atom-ph"],"primary_cat":"physics.optics","authors_text":"Christian Grebing, Christian Hagemann, Christian Lisdat, Fritz Riehle, Jun Ye, Michael J. Martin, Stephan Falke, Thomas Legero, Uwe Sterr","submitted_at":"2014-05-07T21:35:24Z","abstract_excerpt":"Cryogenic single-crystal optical cavities have the potential to provide highest dimensional stability. We have investigated the long-term performance of an ultra-stable laser system which is stabilized to a single-crystal silicon cavity operated at 124 K. Utilizing a frequency comb, the laser is compared to a hydrogen maser that is referenced to a primary caesium fountain standard and to the $^{87}\\mathrm{Sr}$ optical lattice clock at PTB. With fractional frequency instabilities of $\\sigma_y(\\tau)\\leq2\\times10^{-16}$ for averaging times of $\\tau=60\\mathrm{~s}$ to $1000\\mathrm{~s}$ and $\\sigma_"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1405.1759","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":""},"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"}