{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2012:4I3YKMNKX6FCHKEM7EBMVMDWWK","short_pith_number":"pith:4I3YKMNK","canonical_record":{"source":{"id":"1207.3307","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2012-07-13T17:11:21Z","cross_cats_sorted":[],"title_canon_sha256":"417a94b97573e145aabeee161a77c3fabc11028e16cc81372412ea717307f610","abstract_canon_sha256":"63d3944e8ff755767e4175b1d09b8e0f0ee90c4fdb27e2e0871313fc128fc9aa"},"schema_version":"1.0"},"canonical_sha256":"e2378531aabf8a23a88cf902cab076b286dac2dd0c00ad5fafd5043e64b5fb69","source":{"kind":"arxiv","id":"1207.3307","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1207.3307","created_at":"2026-05-18T03:40:25Z"},{"alias_kind":"arxiv_version","alias_value":"1207.3307v2","created_at":"2026-05-18T03:40:25Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1207.3307","created_at":"2026-05-18T03:40:25Z"},{"alias_kind":"pith_short_12","alias_value":"4I3YKMNKX6FC","created_at":"2026-05-18T12:26:53Z"},{"alias_kind":"pith_short_16","alias_value":"4I3YKMNKX6FCHKEM","created_at":"2026-05-18T12:26:53Z"},{"alias_kind":"pith_short_8","alias_value":"4I3YKMNK","created_at":"2026-05-18T12:26:53Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2012:4I3YKMNKX6FCHKEM7EBMVMDWWK","target":"record","payload":{"canonical_record":{"source":{"id":"1207.3307","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2012-07-13T17:11:21Z","cross_cats_sorted":[],"title_canon_sha256":"417a94b97573e145aabeee161a77c3fabc11028e16cc81372412ea717307f610","abstract_canon_sha256":"63d3944e8ff755767e4175b1d09b8e0f0ee90c4fdb27e2e0871313fc128fc9aa"},"schema_version":"1.0"},"canonical_sha256":"e2378531aabf8a23a88cf902cab076b286dac2dd0c00ad5fafd5043e64b5fb69","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T03:40:25.478176Z","signature_b64":"vGblo9KWB5TC434gw1Q45AtSqUKZaTJZemwMpLLvalybeRlOcIsKiB4Ivw8+uSSxK9ufWto2jjq4nJhiSi7tBQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"e2378531aabf8a23a88cf902cab076b286dac2dd0c00ad5fafd5043e64b5fb69","last_reissued_at":"2026-05-18T03:40:25.477340Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T03:40:25.477340Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1207.3307","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T03:40:25Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"/Ifuu5MdGz9TvpyUjsV9ptS5Z++ULPMeK5PGwDsWF9G/Mo8QRT+BRk0jBxbz3jIMSraj+q4615UvFTBy1oSkAg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-30T18:18:36.296117Z"},"content_sha256":"d877aca1068aa13d92bb80aca3667028023bc60e6d7e7e10f3f55af1b9229203","schema_version":"1.0","event_id":"sha256:d877aca1068aa13d92bb80aca3667028023bc60e6d7e7e10f3f55af1b9229203"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2012:4I3YKMNKX6FCHKEM7EBMVMDWWK","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Quantum Metrological Limits via a Variational Approach","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"B. M. Escher, L. Davidovich, N. Zagury, R. L. de Matos Filho","submitted_at":"2012-07-13T17:11:21Z","abstract_excerpt":"The minimum achievable statistical uncertainty in the estimation of physical parameters is determined by the quantum Fisher information. Its computation for noisy systems is still a challenging problem. Using a variational approach, we present an equation for obtaining the quantum Fisher information, which has an explicit dependence on the mathematical description of the noise. This method is applied to obtain a useful analytical bound to the quantum precision in the estimation of phase-shifts under phase diffusion, which shows that the estimation uncertainty cannot be smaller than a noise-dep"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1207.3307","kind":"arxiv","version":2},"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"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T03:40:25Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Ev+oNqsBfVd5BoBADLThAxNey/xyd0l+KM+8n2yrYuNXOIwhD/eEkYSQwv5zjnX4gcp3A7XCrLwJpOrm7zxoCA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-30T18:18:36.296494Z"},"content_sha256":"1c10db10c7eb1a2d102bfb7f1be190766248f63a5018f5a5eedd6eda42facf16","schema_version":"1.0","event_id":"sha256:1c10db10c7eb1a2d102bfb7f1be190766248f63a5018f5a5eedd6eda42facf16"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/4I3YKMNKX6FCHKEM7EBMVMDWWK/bundle.json","state_url":"https://pith.science/pith/4I3YKMNKX6FCHKEM7EBMVMDWWK/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/4I3YKMNKX6FCHKEM7EBMVMDWWK/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-05-30T18:18:36Z","links":{"resolver":"https://pith.science/pith/4I3YKMNKX6FCHKEM7EBMVMDWWK","bundle":"https://pith.science/pith/4I3YKMNKX6FCHKEM7EBMVMDWWK/bundle.json","state":"https://pith.science/pith/4I3YKMNKX6FCHKEM7EBMVMDWWK/state.json","well_known_bundle":"https://pith.science/.well-known/pith/4I3YKMNKX6FCHKEM7EBMVMDWWK/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2012:4I3YKMNKX6FCHKEM7EBMVMDWWK","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":"63d3944e8ff755767e4175b1d09b8e0f0ee90c4fdb27e2e0871313fc128fc9aa","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2012-07-13T17:11:21Z","title_canon_sha256":"417a94b97573e145aabeee161a77c3fabc11028e16cc81372412ea717307f610"},"schema_version":"1.0","source":{"id":"1207.3307","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1207.3307","created_at":"2026-05-18T03:40:25Z"},{"alias_kind":"arxiv_version","alias_value":"1207.3307v2","created_at":"2026-05-18T03:40:25Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1207.3307","created_at":"2026-05-18T03:40:25Z"},{"alias_kind":"pith_short_12","alias_value":"4I3YKMNKX6FC","created_at":"2026-05-18T12:26:53Z"},{"alias_kind":"pith_short_16","alias_value":"4I3YKMNKX6FCHKEM","created_at":"2026-05-18T12:26:53Z"},{"alias_kind":"pith_short_8","alias_value":"4I3YKMNK","created_at":"2026-05-18T12:26:53Z"}],"graph_snapshots":[{"event_id":"sha256:1c10db10c7eb1a2d102bfb7f1be190766248f63a5018f5a5eedd6eda42facf16","target":"graph","created_at":"2026-05-18T03:40:25Z","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 minimum achievable statistical uncertainty in the estimation of physical parameters is determined by the quantum Fisher information. Its computation for noisy systems is still a challenging problem. Using a variational approach, we present an equation for obtaining the quantum Fisher information, which has an explicit dependence on the mathematical description of the noise. This method is applied to obtain a useful analytical bound to the quantum precision in the estimation of phase-shifts under phase diffusion, which shows that the estimation uncertainty cannot be smaller than a noise-dep","authors_text":"B. M. Escher, L. Davidovich, N. Zagury, R. L. de Matos Filho","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2012-07-13T17:11:21Z","title":"Quantum Metrological Limits via a Variational Approach"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1207.3307","kind":"arxiv","version":2},"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:d877aca1068aa13d92bb80aca3667028023bc60e6d7e7e10f3f55af1b9229203","target":"record","created_at":"2026-05-18T03:40:25Z","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":"63d3944e8ff755767e4175b1d09b8e0f0ee90c4fdb27e2e0871313fc128fc9aa","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2012-07-13T17:11:21Z","title_canon_sha256":"417a94b97573e145aabeee161a77c3fabc11028e16cc81372412ea717307f610"},"schema_version":"1.0","source":{"id":"1207.3307","kind":"arxiv","version":2}},"canonical_sha256":"e2378531aabf8a23a88cf902cab076b286dac2dd0c00ad5fafd5043e64b5fb69","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"e2378531aabf8a23a88cf902cab076b286dac2dd0c00ad5fafd5043e64b5fb69","first_computed_at":"2026-05-18T03:40:25.477340Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:40:25.477340Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"vGblo9KWB5TC434gw1Q45AtSqUKZaTJZemwMpLLvalybeRlOcIsKiB4Ivw8+uSSxK9ufWto2jjq4nJhiSi7tBQ==","signature_status":"signed_v1","signed_at":"2026-05-18T03:40:25.478176Z","signed_message":"canonical_sha256_bytes"},"source_id":"1207.3307","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:d877aca1068aa13d92bb80aca3667028023bc60e6d7e7e10f3f55af1b9229203","sha256:1c10db10c7eb1a2d102bfb7f1be190766248f63a5018f5a5eedd6eda42facf16"],"state_sha256":"fad0851cecc3f75c0f69e7cce1cb9ccdfb5df7e1349259709eb0c9a811d70742"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"7UtkIjDquX4GSXItpXhLWswhGZH4ZBp4RuPhbHOqrkVV6pYCTTg01UbcThVf32dwNNdqgOIfokaBHsMp+1+wCQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-30T18:18:36.298451Z","bundle_sha256":"7faeb6260b6275930194e947e5511eb9ea13558668216e119e8cebdaf1f3129f"}}