{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2026:XQRKQDVQ2RTP65QNUZOGH3JHCX","short_pith_number":"pith:XQRKQDVQ","schema_version":"1.0","canonical_sha256":"bc22a80eb0d466ff760da65c63ed2715ea9860290d4df0cba1be3aaf260fa3a7","source":{"kind":"arxiv","id":"2606.04997","version":1},"attestation_state":"computed","paper":{"title":"A thorium-229 optical nuclear clock with feedback loop","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["nucl-ex","quant-ph"],"primary_cat":"physics.atom-ph","authors_text":"A. Hellerschmied, A. Niessner, B. Gerstenecker, E. Peik, F. Schaden, F. Schneider, G. A. Kazakov, G. Zitzer, H. Denker, I. Morawetz, J. Premper, J. Schlachet-L\\'epinay, J. Tiedau, K. Beeks, L. Toscani De Col, M. Bartokos, M. Cizek, M. Matus, M. Pimon, M. V. Okhapkin, N. Sempelmann, O. Cip, S. Lahs, T. Lercher, T. Riebner, T. Schumm, V. Lal, V. Petrov","submitted_at":"2026-06-03T15:15:56Z","abstract_excerpt":"The laser-accessible nuclear transition in the thorium-229 isotope has been identified as a promising candidate for the realization of an optical nuclear clock. Such a nuclear clock might rival or outperform current optical clocks based on electron-shell transitions in atoms or ions, is expected to be more robust against external perturbations, and provides enhanced sensitivity in clock-based tests of fundamental principles of physics. Here, we implement a thorium-229 nuclear clock by stabilizing a continuous-wave laser to the 148 nm nuclear transition with rapid feedback based on continuous a"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"2606.04997","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"physics.atom-ph","submitted_at":"2026-06-03T15:15:56Z","cross_cats_sorted":["nucl-ex","quant-ph"],"title_canon_sha256":"15a09ac81dd53536a6abd874b9782d46deb1d8f38b865eca659e5c11acfcc187","abstract_canon_sha256":"20c8b1bfaa86274be70481f893b057a89ceefce7d4f2338b021090381adba65d"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-06-04T01:10:00.643997Z","signature_b64":"FPpNF1DWcy3TCT6otMmM2gZ4xlO6X/ELx0VeH8dJlcosRDPCrB8QBKnXluFty91eRwZZ3Kos6aRvsEoOVVEWAQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"bc22a80eb0d466ff760da65c63ed2715ea9860290d4df0cba1be3aaf260fa3a7","last_reissued_at":"2026-06-04T01:10:00.642892Z","signature_status":"signed_v1","first_computed_at":"2026-06-04T01:10:00.642892Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"A thorium-229 optical nuclear clock with feedback loop","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["nucl-ex","quant-ph"],"primary_cat":"physics.atom-ph","authors_text":"A. Hellerschmied, A. Niessner, B. Gerstenecker, E. Peik, F. Schaden, F. Schneider, G. A. Kazakov, G. Zitzer, H. Denker, I. Morawetz, J. Premper, J. Schlachet-L\\'epinay, J. Tiedau, K. Beeks, L. Toscani De Col, M. Bartokos, M. Cizek, M. Matus, M. Pimon, M. V. Okhapkin, N. Sempelmann, O. Cip, S. Lahs, T. Lercher, T. Riebner, T. Schumm, V. Lal, V. Petrov","submitted_at":"2026-06-03T15:15:56Z","abstract_excerpt":"The laser-accessible nuclear transition in the thorium-229 isotope has been identified as a promising candidate for the realization of an optical nuclear clock. Such a nuclear clock might rival or outperform current optical clocks based on electron-shell transitions in atoms or ions, is expected to be more robust against external perturbations, and provides enhanced sensitivity in clock-based tests of fundamental principles of physics. Here, we implement a thorium-229 nuclear clock by stabilizing a continuous-wave laser to the 148 nm nuclear transition with rapid feedback based on continuous a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.04997","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/2606.04997/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"},"aliases":[{"alias_kind":"arxiv","alias_value":"2606.04997","created_at":"2026-06-04T01:10:00.643219+00:00"},{"alias_kind":"arxiv_version","alias_value":"2606.04997v1","created_at":"2026-06-04T01:10:00.643219+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2606.04997","created_at":"2026-06-04T01:10:00.643219+00:00"},{"alias_kind":"pith_short_12","alias_value":"XQRKQDVQ2RTP","created_at":"2026-06-04T01:10:00.643219+00:00"},{"alias_kind":"pith_short_16","alias_value":"XQRKQDVQ2RTP65QN","created_at":"2026-06-04T01:10:00.643219+00:00"},{"alias_kind":"pith_short_8","alias_value":"XQRKQDVQ","created_at":"2026-06-04T01:10:00.643219+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":0,"internal_anchor_count":0,"sample":[]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX","json":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX.json","graph_json":"https://pith.science/api/pith-number/XQRKQDVQ2RTP65QNUZOGH3JHCX/graph.json","events_json":"https://pith.science/api/pith-number/XQRKQDVQ2RTP65QNUZOGH3JHCX/events.json","paper":"https://pith.science/paper/XQRKQDVQ"},"agent_actions":{"view_html":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX","download_json":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX.json","view_paper":"https://pith.science/paper/XQRKQDVQ","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2606.04997&json=true","fetch_graph":"https://pith.science/api/pith-number/XQRKQDVQ2RTP65QNUZOGH3JHCX/graph.json","fetch_events":"https://pith.science/api/pith-number/XQRKQDVQ2RTP65QNUZOGH3JHCX/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX/action/timestamp_anchor","attest_storage":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX/action/storage_attestation","attest_author":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX/action/author_attestation","sign_citation":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX/action/citation_signature","submit_replication":"https://pith.science/pith/XQRKQDVQ2RTP65QNUZOGH3JHCX/action/replication_record"}},"created_at":"2026-06-04T01:10:00.643219+00:00","updated_at":"2026-06-04T01:10:00.643219+00:00"}