{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2015:WQLBGYYPPZ6ZJQQXT3ID6HSBVU","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"58357046657749fe147c62586f47c5c1fde0739041b51a498029b7a41607a190","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.optics","submitted_at":"2015-09-25T20:46:24Z","title_canon_sha256":"6fd96e42fbd82d1d4eee04450c4dd7ed87885ad2cb450c2057143512082c5542"},"schema_version":"1.0","source":{"id":"1509.07888","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1509.07888","created_at":"2026-05-18T01:14:44Z"},{"alias_kind":"arxiv_version","alias_value":"1509.07888v3","created_at":"2026-05-18T01:14:44Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1509.07888","created_at":"2026-05-18T01:14:44Z"},{"alias_kind":"pith_short_12","alias_value":"WQLBGYYPPZ6Z","created_at":"2026-05-18T12:29:47Z"},{"alias_kind":"pith_short_16","alias_value":"WQLBGYYPPZ6ZJQQX","created_at":"2026-05-18T12:29:47Z"},{"alias_kind":"pith_short_8","alias_value":"WQLBGYYP","created_at":"2026-05-18T12:29:47Z"}],"graph_snapshots":[{"event_id":"sha256:63af7fa99061f0116ea099155533279d1e3df193739fbd69dd34880cc346b0fa","target":"graph","created_at":"2026-05-18T01:14:44Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"The use of optical clocks/oscillators in future ultra-precise navigation, gravitational sensing, coherent arrays, and relativity experiments will require time comparison and synchronization over terrestrial or satellite free-space links. Here we demonstrate full unambiguous synchronization of two optical timescales across a free-space link. The time deviation between synchronized timescales is below 1 fs over durations from 0.1 s to 6500 s, despite atmospheric turbulence and kilometer-scale path length variations. Over several days, the time wander is 40 fs peak-to-peak. Our approach relies on","authors_text":"Esther Baumann, Fabrizio R. Giorgetta, Hugo Bergeron, Ian Coddington, Jean-Daniel Deschenes, Laura C. Sinclair, Michael Cermak, Nathan R. Newbury, William C. Swann","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.optics","submitted_at":"2015-09-25T20:46:24Z","title":"Synchronization of Distant Optical Clocks at the Femtosecond Level"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1509.07888","kind":"arxiv","version":3},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:6d461d3cfadc9f30f523cbf96d6ccaef142b5de2c0d4084ca9a5e7c28d004e19","target":"record","created_at":"2026-05-18T01:14:44Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"58357046657749fe147c62586f47c5c1fde0739041b51a498029b7a41607a190","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.optics","submitted_at":"2015-09-25T20:46:24Z","title_canon_sha256":"6fd96e42fbd82d1d4eee04450c4dd7ed87885ad2cb450c2057143512082c5542"},"schema_version":"1.0","source":{"id":"1509.07888","kind":"arxiv","version":3}},"canonical_sha256":"b41613630f7e7d94c2179ed03f1e41ad0b0bc193b6139f49ba75cb61e649e8a4","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"b41613630f7e7d94c2179ed03f1e41ad0b0bc193b6139f49ba75cb61e649e8a4","first_computed_at":"2026-05-18T01:14:44.956789Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:14:44.956789Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"hEi9tQDUHWpnzWTSAANv8Y+VBiakxfZTI+o2PJLdRGqR8xTwxuw+gOCBO5M7WKUNDPkPTZNJReOY0lERYrI0Bw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:14:44.957459Z","signed_message":"canonical_sha256_bytes"},"source_id":"1509.07888","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:6d461d3cfadc9f30f523cbf96d6ccaef142b5de2c0d4084ca9a5e7c28d004e19","sha256:63af7fa99061f0116ea099155533279d1e3df193739fbd69dd34880cc346b0fa"],"state_sha256":"ac01611d7c4fef33721adf6ff2efa57c010be24d2caa4eb151e06b6acd4bcde0"}