{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"5a37b6d4292510bac00765688e2ae5596be0f806bceee80837eed8c7a8fb4a81","created":"2026-10-03T07:17:54Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"f08ae2f6fbe0d2c654956cc532932041ca6bfd36dabf279eb83d7fab4cd5e788","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"amo.noisy-quantum-metrology.clock-lo-noise","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"A clock steers a laser using N atoms, but the laser itself jitters, which limits how long atoms can be probed. The best possible improvement from entangling the atoms, given this jitter, is not known.","posed_since":"","precise":"For a Ramsey-type optical clock with $N$ atoms and local-oscillator frequency noise with power spectrum $S(f)\\sim h_\\alpha f^{-\\alpha} (\\alpha=0, 1, 2)$, determine the optimal asymptotic scaling with $N$ of the long-term Allan deviation $\\sigma_y(\\tau)$, optimizing over entangled states, adaptive measurements and feedback, and whether any protocol reaches $1/N$ scaling up to logarithmic factors.","problem_ref":null,"references":"","settled_by":"A matching lower bound and explicit protocol for the Allan deviation exponent as a function of N for each noise type.","status_note":"Protocols with near-Heisenberg scaling up to logarithmic factors are known for white phase noise; matching bounds for 1/f and random-walk laser noise are lacking.","title":"Optimal scaling of atomic-clock stability with atom number under laser noise","topic_ref":"b95a8ff18c070433c3fe82a6890e1ebb1ad0aa64cad14ab4a8806dfeb3a86077"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"389c8ba93124de72ae8dec526b022c3a720604a74348bf391ad7c6fa3b77e42d","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"0cd3ed3a9cb2279bcb47ea1fd57cf9ce1b6a430d57e53c0d018e1b58e18354bf","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"_ix9evw4RgvuW-0dubCYv1c2vOZqOqyXruVZQrthnsbTHgVweLHgI2WKhHg3zD4QPZENiqVRrOr4WajGxwMUBw"},"schema":"pubphys.envelope/1"},"record_hash":"389c8ba93124de72ae8dec526b022c3a720604a74348bf391ad7c6fa3b77e42d","leaf_index":433}