{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:M6IABRXTHZHOK2SDPFPJSWP7QM","short_pith_number":"pith:M6IABRXT","canonical_record":{"source":{"id":"1806.08922","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2018-06-23T07:24:48Z","cross_cats_sorted":["gr-qc","quant-ph"],"title_canon_sha256":"9b383220e0675620fb69bd6138879105ef333f587285ef41a25db50d8fb90f78","abstract_canon_sha256":"aba15e47a1926a96cf9e6735301471a371239c2f205af71cca13405e2d211d63"},"schema_version":"1.0"},"canonical_sha256":"679000c6f33e4ee56a43795e9959ff83128ba85eb8b077bcb47b822cb7ca896f","source":{"kind":"arxiv","id":"1806.08922","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1806.08922","created_at":"2026-05-18T00:06:01Z"},{"alias_kind":"arxiv_version","alias_value":"1806.08922v2","created_at":"2026-05-18T00:06:01Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1806.08922","created_at":"2026-05-18T00:06:01Z"},{"alias_kind":"pith_short_12","alias_value":"M6IABRXTHZHO","created_at":"2026-05-18T12:32:37Z"},{"alias_kind":"pith_short_16","alias_value":"M6IABRXTHZHOK2SD","created_at":"2026-05-18T12:32:37Z"},{"alias_kind":"pith_short_8","alias_value":"M6IABRXT","created_at":"2026-05-18T12:32:37Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:M6IABRXTHZHOK2SDPFPJSWP7QM","target":"record","payload":{"canonical_record":{"source":{"id":"1806.08922","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2018-06-23T07:24:48Z","cross_cats_sorted":["gr-qc","quant-ph"],"title_canon_sha256":"9b383220e0675620fb69bd6138879105ef333f587285ef41a25db50d8fb90f78","abstract_canon_sha256":"aba15e47a1926a96cf9e6735301471a371239c2f205af71cca13405e2d211d63"},"schema_version":"1.0"},"canonical_sha256":"679000c6f33e4ee56a43795e9959ff83128ba85eb8b077bcb47b822cb7ca896f","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:06:01.504633Z","signature_b64":"Yu56dQVpQIVaYoPLOflrWjpUeMARmiqNIsGImC+6vyP8HyV8118Yj7LDygQSRLJ9R3DvxaRk63oJjgbzCyFUDA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"679000c6f33e4ee56a43795e9959ff83128ba85eb8b077bcb47b822cb7ca896f","last_reissued_at":"2026-05-18T00:06:01.504206Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:06:01.504206Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1806.08922","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":"2026-05-18T00:06:01Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"P624TPuxCzElRsQXJ4kojwO7/2NKm0McnwYnfhtSd7J1RQqQ97cCi0zi8uEP4c1xyhI9tS+6R+k5oCQXaoEoAg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-07T16:14:20.217481Z"},"content_sha256":"d12b9206cb26fe439891cd945b3bf9f77bf9d9c24c7c45c453eacfd59fb0a247","schema_version":"1.0","event_id":"sha256:d12b9206cb26fe439891cd945b3bf9f77bf9d9c24c7c45c453eacfd59fb0a247"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:M6IABRXTHZHOK2SDPFPJSWP7QM","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Quantum estimation in an expanding spacetime","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["gr-qc","quant-ph"],"primary_cat":"hep-th","authors_text":"Heng Fan, Jun Feng, Xiaoyang Huang, Yao-Zhong Zhang","submitted_at":"2018-06-23T07:24:48Z","abstract_excerpt":"We investigate the quantum estimation on the Hubble parameter of an expanding de Sitter space by quantum metrological techniques. By exploring the dynamics of a freely falling Unruh-DeWitt detector, which interacts with a scalar field coupling to curvature, we calculate the Fisher information (FI) and quantum Fisher information (QFI) for the detector, which bound the highest precision of the estimation on Hubble parameter. In standard Bunch-Davies vacuum, we show that the maxima of FI/QFI are located for particular initial state of probe. Beside its dependence on the evolving time of detector "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1806.08922","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":"2026-05-18T00:06:01Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"RFJgRfMy2W+WYerebdBpa5xJnIvgh0n8+Hd3cx6/d0xuIv6d/awJfrPpyWqsYxJOZ4o+V8JKTLpKc4nCHKPVCg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-07T16:14:20.218225Z"},"content_sha256":"0cff7870b595ac3b4e759deb6e8af904bb3186a20409cafc8bae98da9ba74b25","schema_version":"1.0","event_id":"sha256:0cff7870b595ac3b4e759deb6e8af904bb3186a20409cafc8bae98da9ba74b25"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/M6IABRXTHZHOK2SDPFPJSWP7QM/bundle.json","state_url":"https://pith.science/pith/M6IABRXTHZHOK2SDPFPJSWP7QM/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/M6IABRXTHZHOK2SDPFPJSWP7QM/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":"2026-06-07T16:14:20Z","links":{"resolver":"https://pith.science/pith/M6IABRXTHZHOK2SDPFPJSWP7QM","bundle":"https://pith.science/pith/M6IABRXTHZHOK2SDPFPJSWP7QM/bundle.json","state":"https://pith.science/pith/M6IABRXTHZHOK2SDPFPJSWP7QM/state.json","well_known_bundle":"https://pith.science/.well-known/pith/M6IABRXTHZHOK2SDPFPJSWP7QM/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:M6IABRXTHZHOK2SDPFPJSWP7QM","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":"aba15e47a1926a96cf9e6735301471a371239c2f205af71cca13405e2d211d63","cross_cats_sorted":["gr-qc","quant-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2018-06-23T07:24:48Z","title_canon_sha256":"9b383220e0675620fb69bd6138879105ef333f587285ef41a25db50d8fb90f78"},"schema_version":"1.0","source":{"id":"1806.08922","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1806.08922","created_at":"2026-05-18T00:06:01Z"},{"alias_kind":"arxiv_version","alias_value":"1806.08922v2","created_at":"2026-05-18T00:06:01Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1806.08922","created_at":"2026-05-18T00:06:01Z"},{"alias_kind":"pith_short_12","alias_value":"M6IABRXTHZHO","created_at":"2026-05-18T12:32:37Z"},{"alias_kind":"pith_short_16","alias_value":"M6IABRXTHZHOK2SD","created_at":"2026-05-18T12:32:37Z"},{"alias_kind":"pith_short_8","alias_value":"M6IABRXT","created_at":"2026-05-18T12:32:37Z"}],"graph_snapshots":[{"event_id":"sha256:0cff7870b595ac3b4e759deb6e8af904bb3186a20409cafc8bae98da9ba74b25","target":"graph","created_at":"2026-05-18T00:06:01Z","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":"We investigate the quantum estimation on the Hubble parameter of an expanding de Sitter space by quantum metrological techniques. By exploring the dynamics of a freely falling Unruh-DeWitt detector, which interacts with a scalar field coupling to curvature, we calculate the Fisher information (FI) and quantum Fisher information (QFI) for the detector, which bound the highest precision of the estimation on Hubble parameter. In standard Bunch-Davies vacuum, we show that the maxima of FI/QFI are located for particular initial state of probe. Beside its dependence on the evolving time of detector ","authors_text":"Heng Fan, Jun Feng, Xiaoyang Huang, Yao-Zhong Zhang","cross_cats":["gr-qc","quant-ph"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2018-06-23T07:24:48Z","title":"Quantum estimation in an expanding spacetime"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1806.08922","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:d12b9206cb26fe439891cd945b3bf9f77bf9d9c24c7c45c453eacfd59fb0a247","target":"record","created_at":"2026-05-18T00:06:01Z","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":"aba15e47a1926a96cf9e6735301471a371239c2f205af71cca13405e2d211d63","cross_cats_sorted":["gr-qc","quant-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2018-06-23T07:24:48Z","title_canon_sha256":"9b383220e0675620fb69bd6138879105ef333f587285ef41a25db50d8fb90f78"},"schema_version":"1.0","source":{"id":"1806.08922","kind":"arxiv","version":2}},"canonical_sha256":"679000c6f33e4ee56a43795e9959ff83128ba85eb8b077bcb47b822cb7ca896f","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"679000c6f33e4ee56a43795e9959ff83128ba85eb8b077bcb47b822cb7ca896f","first_computed_at":"2026-05-18T00:06:01.504206Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:06:01.504206Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"Yu56dQVpQIVaYoPLOflrWjpUeMARmiqNIsGImC+6vyP8HyV8118Yj7LDygQSRLJ9R3DvxaRk63oJjgbzCyFUDA==","signature_status":"signed_v1","signed_at":"2026-05-18T00:06:01.504633Z","signed_message":"canonical_sha256_bytes"},"source_id":"1806.08922","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:d12b9206cb26fe439891cd945b3bf9f77bf9d9c24c7c45c453eacfd59fb0a247","sha256:0cff7870b595ac3b4e759deb6e8af904bb3186a20409cafc8bae98da9ba74b25"],"state_sha256":"84c0fd5a5758af20998bd7655d6ec525a986b0398d891f0daf4a7359b195e2da"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"YRfhMZxAMZgWDPNx7862mfFzyRx2jBrbXmTN1vGz0dhNQiAjx2ZSnWSib5CJfWwQ0PrWqyGwtkuOLh06vSOdAg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-07T16:14:20.222193Z","bundle_sha256":"c140bf7327c8330f865517df4f8f590dd2d6f016065fbc283439a4b6d4519a6d"}}