{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.topic/1","content_sha256":"e097c1396ff228487ce4c128057cb5c8314f016948448fe9bdc1b3ecca8deb70","created":"2026-10-03T07:17:49Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":[],"salt":"7d38c918ea6475757e27b07cdb66a0f83ae2e7c1e41995c22ab30051c92bbc50","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"topic"},"content":{"external_id":"amo.optical-clocks-second","field":"amo","n":"1","review_cite":"N. Dimarcq et al., Roadmap towards the redefinition of the second, Metrologia, 2024","review_link":"https://doi.org/10.1088/1681-7575/ad17d2","review_verified":"true","summary":"The second is defined by a microwave transition in cesium, but clocks using optical transitions are now about 100 times more accurate. Choosing what replaces cesium, and pushing clocks further, involves both physics and international agreement.","title":"Next-generation clocks and redefining the second","topic_ref":null,"why":"Better clocks redefine the unit of time and serve as sensors for geodesy, dark matter and changes of constants."},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"5d572b616becc2d77dc7833412720dbdbc6e7e6aa45f95467fa95e2923acf321","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"f5bd0ed88a95d24711ce6980e65528526aff7f4080baa0c1be6178a87a21dacb","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Sfq7Rt8Z-2N8SftGCwy1o9K5W_kJJJELSIBlum1VpunUEInttbY6vYhF7llJ2NSgnNq_NkaKenXR1lDcSmkMCg"},"schema":"pubphys.envelope/1"},"record_hash":"5d572b616becc2d77dc7833412720dbdbc6e7e6aa45f95467fa95e2923acf321","leaf_index":21}