{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:W3COPHC4GE4N77PBWWRF42DU2E","short_pith_number":"pith:W3COPHC4","canonical_record":{"source":{"id":"1812.02835","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-12-06T22:27:40Z","cross_cats_sorted":["quant-ph"],"title_canon_sha256":"1e838d43d1e66ce44bfef8c942bb25ca1e9c4992eb0166076039c9b9e6408221","abstract_canon_sha256":"0fb06aeed6529379f11d96e6093d875fd4d307ae2c09b2438d84b212820af0ce"},"schema_version":"1.0"},"canonical_sha256":"b6c4e79c5c3138dffde1b5a25e6874d10045d1ce751a5f80ffe8a136044bc495","source":{"kind":"arxiv","id":"1812.02835","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1812.02835","created_at":"2026-05-17T23:51:30Z"},{"alias_kind":"arxiv_version","alias_value":"1812.02835v1","created_at":"2026-05-17T23:51:30Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1812.02835","created_at":"2026-05-17T23:51:30Z"},{"alias_kind":"pith_short_12","alias_value":"W3COPHC4GE4N","created_at":"2026-05-18T12:32:59Z"},{"alias_kind":"pith_short_16","alias_value":"W3COPHC4GE4N77PB","created_at":"2026-05-18T12:32:59Z"},{"alias_kind":"pith_short_8","alias_value":"W3COPHC4","created_at":"2026-05-18T12:32:59Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:W3COPHC4GE4N77PBWWRF42DU2E","target":"record","payload":{"canonical_record":{"source":{"id":"1812.02835","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-12-06T22:27:40Z","cross_cats_sorted":["quant-ph"],"title_canon_sha256":"1e838d43d1e66ce44bfef8c942bb25ca1e9c4992eb0166076039c9b9e6408221","abstract_canon_sha256":"0fb06aeed6529379f11d96e6093d875fd4d307ae2c09b2438d84b212820af0ce"},"schema_version":"1.0"},"canonical_sha256":"b6c4e79c5c3138dffde1b5a25e6874d10045d1ce751a5f80ffe8a136044bc495","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:51:30.635691Z","signature_b64":"l3c1frchxSVZJonrZ4VRP2WtukE3KawN+NIpDP6pmz6WQoX2NeyUnEpoGHSxOgyGqpqvBkc+KBTdUu1D3jyJDw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"b6c4e79c5c3138dffde1b5a25e6874d10045d1ce751a5f80ffe8a136044bc495","last_reissued_at":"2026-05-17T23:51:30.635273Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:51:30.635273Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1812.02835","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-17T23:51:30Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ZKL2BtanJFwTYIDVfJgcBjJOTER66palGvgNKsNtAgRmYZQpenFLge6eHRggXzIESqIC4OgSbq+MWcx/lYk/AQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-01T17:52:23.584216Z"},"content_sha256":"98b86132b12be3332b086176c250a2d579c61d139f3a60b798c0d034dd10d7e2","schema_version":"1.0","event_id":"sha256:98b86132b12be3332b086176c250a2d579c61d139f3a60b798c0d034dd10d7e2"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:W3COPHC4GE4N77PBWWRF42DU2E","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Entanglement in anisotropic expanding spacetime","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["quant-ph"],"primary_cat":"gr-qc","authors_text":"Roberto Pierini, Shahpoor Moradi, Stefano Mancini","submitted_at":"2018-12-06T22:27:40Z","abstract_excerpt":"We study the effect of space anisotropy in the entanglement generated by expanding universe on spin 0 and 1/2 fields. For massive scalar field we find revivals of entanglement entropy vs momentum after decreasing from the maximum at k = 0. In massive Dirac field the effect is a slight distortion of the non-monotonic profile giving rise to the maximum of entanglement entropy at k > 0. More interestingly, massless field of both type can only get entangled through anisotropy, with a maximum of entanglement entropy occurring at k > 0."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1812.02835","kind":"arxiv","version":1},"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":"2026-05-17T23:51:30Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"p0aIp/avzJKBuyYnwvSvRTduYpYJ2a4agxOTEpNcjOsOLGzu4TC+7/GLymmdwjEQFNfjMaRBaJupT1IqIlE4Dw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-01T17:52:23.584571Z"},"content_sha256":"1e88a7fbc9f1479132bf5350985f336d4f9273518c7b9d7dd04254a98ba67dc1","schema_version":"1.0","event_id":"sha256:1e88a7fbc9f1479132bf5350985f336d4f9273518c7b9d7dd04254a98ba67dc1"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/W3COPHC4GE4N77PBWWRF42DU2E/bundle.json","state_url":"https://pith.science/pith/W3COPHC4GE4N77PBWWRF42DU2E/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/W3COPHC4GE4N77PBWWRF42DU2E/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":"2026-06-01T17:52:23Z","links":{"resolver":"https://pith.science/pith/W3COPHC4GE4N77PBWWRF42DU2E","bundle":"https://pith.science/pith/W3COPHC4GE4N77PBWWRF42DU2E/bundle.json","state":"https://pith.science/pith/W3COPHC4GE4N77PBWWRF42DU2E/state.json","well_known_bundle":"https://pith.science/.well-known/pith/W3COPHC4GE4N77PBWWRF42DU2E/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:W3COPHC4GE4N77PBWWRF42DU2E","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":"0fb06aeed6529379f11d96e6093d875fd4d307ae2c09b2438d84b212820af0ce","cross_cats_sorted":["quant-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-12-06T22:27:40Z","title_canon_sha256":"1e838d43d1e66ce44bfef8c942bb25ca1e9c4992eb0166076039c9b9e6408221"},"schema_version":"1.0","source":{"id":"1812.02835","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1812.02835","created_at":"2026-05-17T23:51:30Z"},{"alias_kind":"arxiv_version","alias_value":"1812.02835v1","created_at":"2026-05-17T23:51:30Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1812.02835","created_at":"2026-05-17T23:51:30Z"},{"alias_kind":"pith_short_12","alias_value":"W3COPHC4GE4N","created_at":"2026-05-18T12:32:59Z"},{"alias_kind":"pith_short_16","alias_value":"W3COPHC4GE4N77PB","created_at":"2026-05-18T12:32:59Z"},{"alias_kind":"pith_short_8","alias_value":"W3COPHC4","created_at":"2026-05-18T12:32:59Z"}],"graph_snapshots":[{"event_id":"sha256:1e88a7fbc9f1479132bf5350985f336d4f9273518c7b9d7dd04254a98ba67dc1","target":"graph","created_at":"2026-05-17T23:51:30Z","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 study the effect of space anisotropy in the entanglement generated by expanding universe on spin 0 and 1/2 fields. For massive scalar field we find revivals of entanglement entropy vs momentum after decreasing from the maximum at k = 0. In massive Dirac field the effect is a slight distortion of the non-monotonic profile giving rise to the maximum of entanglement entropy at k > 0. More interestingly, massless field of both type can only get entangled through anisotropy, with a maximum of entanglement entropy occurring at k > 0.","authors_text":"Roberto Pierini, Shahpoor Moradi, Stefano Mancini","cross_cats":["quant-ph"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-12-06T22:27:40Z","title":"Entanglement in anisotropic expanding spacetime"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1812.02835","kind":"arxiv","version":1},"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":"sha256:98b86132b12be3332b086176c250a2d579c61d139f3a60b798c0d034dd10d7e2","target":"record","created_at":"2026-05-17T23:51:30Z","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":"0fb06aeed6529379f11d96e6093d875fd4d307ae2c09b2438d84b212820af0ce","cross_cats_sorted":["quant-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-12-06T22:27:40Z","title_canon_sha256":"1e838d43d1e66ce44bfef8c942bb25ca1e9c4992eb0166076039c9b9e6408221"},"schema_version":"1.0","source":{"id":"1812.02835","kind":"arxiv","version":1}},"canonical_sha256":"b6c4e79c5c3138dffde1b5a25e6874d10045d1ce751a5f80ffe8a136044bc495","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"b6c4e79c5c3138dffde1b5a25e6874d10045d1ce751a5f80ffe8a136044bc495","first_computed_at":"2026-05-17T23:51:30.635273Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:51:30.635273Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"l3c1frchxSVZJonrZ4VRP2WtukE3KawN+NIpDP6pmz6WQoX2NeyUnEpoGHSxOgyGqpqvBkc+KBTdUu1D3jyJDw==","signature_status":"signed_v1","signed_at":"2026-05-17T23:51:30.635691Z","signed_message":"canonical_sha256_bytes"},"source_id":"1812.02835","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:98b86132b12be3332b086176c250a2d579c61d139f3a60b798c0d034dd10d7e2","sha256:1e88a7fbc9f1479132bf5350985f336d4f9273518c7b9d7dd04254a98ba67dc1"],"state_sha256":"d0f3a0ce62b07b518f6202b4c876eccf725793f4d9a0db939b333a77c023241e"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"INkxiKMDPA0iZOH78vHF5nKI4g5nexgkMQmIdv/aCdODSPZgXF/zQCsFa7yOaEKj2PPfFUqgyrDVPsERuMbYCQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-01T17:52:23.586389Z","bundle_sha256":"092ffd8eab8b2e626368c5edc36d1e93ccbbfe5db58bef57f72bd1137a4a537c"}}