{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2008:GSIHJB5SPGXYWYESB2XREQSOQM","short_pith_number":"pith:GSIHJB5S","canonical_record":{"source":{"id":"0811.4527","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2008-11-27T12:48:06Z","cross_cats_sorted":[],"title_canon_sha256":"7d0b8cb733263ca7815f671d83d9ed0b4be3c60c87bb9a3d0bc89e08927ad81e","abstract_canon_sha256":"9932b9dcf1af38b8d8315153b0a6112448e272d683886295401bc235dad91342"},"schema_version":"1.0"},"canonical_sha256":"34907487b279af8b60920eaf12424e83081dcad303cc1cc7cffe9485ef38e0c1","source":{"kind":"arxiv","id":"0811.4527","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"0811.4527","created_at":"2026-05-18T02:15:12Z"},{"alias_kind":"arxiv_version","alias_value":"0811.4527v3","created_at":"2026-05-18T02:15:12Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.0811.4527","created_at":"2026-05-18T02:15:12Z"},{"alias_kind":"pith_short_12","alias_value":"GSIHJB5SPGXY","created_at":"2026-05-18T12:25:57Z"},{"alias_kind":"pith_short_16","alias_value":"GSIHJB5SPGXYWYES","created_at":"2026-05-18T12:25:57Z"},{"alias_kind":"pith_short_8","alias_value":"GSIHJB5S","created_at":"2026-05-18T12:25:57Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2008:GSIHJB5SPGXYWYESB2XREQSOQM","target":"record","payload":{"canonical_record":{"source":{"id":"0811.4527","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2008-11-27T12:48:06Z","cross_cats_sorted":[],"title_canon_sha256":"7d0b8cb733263ca7815f671d83d9ed0b4be3c60c87bb9a3d0bc89e08927ad81e","abstract_canon_sha256":"9932b9dcf1af38b8d8315153b0a6112448e272d683886295401bc235dad91342"},"schema_version":"1.0"},"canonical_sha256":"34907487b279af8b60920eaf12424e83081dcad303cc1cc7cffe9485ef38e0c1","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:15:12.848044Z","signature_b64":"sqBtle00qEkQlS1f+0lRIqHWnmIK9VpnXIOvECxpA6EsZt7FM/wA+tAzBA6VE22eAhcEwshWJmQojsSIHyNSAw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"34907487b279af8b60920eaf12424e83081dcad303cc1cc7cffe9485ef38e0c1","last_reissued_at":"2026-05-18T02:15:12.847274Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:15:12.847274Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"0811.4527","source_version":3,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T02:15:12Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"xrGjQItVMxMrLlsZR9bXPGPSz+lAM8UNl6CE5E9d8mJqDwfghqSYVJlrlPjiG50XxLABoIUq9McuyO8JLltbCQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-02T11:24:37.549827Z"},"content_sha256":"798ccf2779f690b1c1c43141b0cc190c3b9577b00703019fac957784a45de5ae","schema_version":"1.0","event_id":"sha256:798ccf2779f690b1c1c43141b0cc190c3b9577b00703019fac957784a45de5ae"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2008:GSIHJB5SPGXYWYESB2XREQSOQM","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Representation of entanglement by negative quasi-probabilities","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"J. Sperling, W. Vogel","submitted_at":"2008-11-27T12:48:06Z","abstract_excerpt":"Any bipartite quantum state has quasi-probability representations in terms of separable states. For entangled states these quasi-probabilities necessarily exhibit negativities. Based on the general structure of composite quantum states, one may reconstruct such quasi-propabilities from experimental data. Because of ambiguity, the quasi-probabilities obtained by the bare reconstruction are insufficient to identify entanglement. An optimization procedure is introduced to derive quasi-probabilities with a minimal amount of negativity. Negativities of optimized quasi-probabilities unambiguously pr"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0811.4527","kind":"arxiv","version":3},"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":"2026-05-18T02:15:12Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"w9Ic69iDf415mTxbbaI1Tt0N38IpEA1Jqth6df9j/OG3Bewdymk3PPGrNHmm2TYnzhVNJZiiG8q6jKIKXD60Dg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-02T11:24:37.550159Z"},"content_sha256":"975b2d22b12e17ffceae4937d86695530e8dfb8e615119f532521183db3be852","schema_version":"1.0","event_id":"sha256:975b2d22b12e17ffceae4937d86695530e8dfb8e615119f532521183db3be852"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/GSIHJB5SPGXYWYESB2XREQSOQM/bundle.json","state_url":"https://pith.science/pith/GSIHJB5SPGXYWYESB2XREQSOQM/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/GSIHJB5SPGXYWYESB2XREQSOQM/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":"2026-06-02T11:24:37Z","links":{"resolver":"https://pith.science/pith/GSIHJB5SPGXYWYESB2XREQSOQM","bundle":"https://pith.science/pith/GSIHJB5SPGXYWYESB2XREQSOQM/bundle.json","state":"https://pith.science/pith/GSIHJB5SPGXYWYESB2XREQSOQM/state.json","well_known_bundle":"https://pith.science/.well-known/pith/GSIHJB5SPGXYWYESB2XREQSOQM/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2008:GSIHJB5SPGXYWYESB2XREQSOQM","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":"9932b9dcf1af38b8d8315153b0a6112448e272d683886295401bc235dad91342","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2008-11-27T12:48:06Z","title_canon_sha256":"7d0b8cb733263ca7815f671d83d9ed0b4be3c60c87bb9a3d0bc89e08927ad81e"},"schema_version":"1.0","source":{"id":"0811.4527","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"0811.4527","created_at":"2026-05-18T02:15:12Z"},{"alias_kind":"arxiv_version","alias_value":"0811.4527v3","created_at":"2026-05-18T02:15:12Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.0811.4527","created_at":"2026-05-18T02:15:12Z"},{"alias_kind":"pith_short_12","alias_value":"GSIHJB5SPGXY","created_at":"2026-05-18T12:25:57Z"},{"alias_kind":"pith_short_16","alias_value":"GSIHJB5SPGXYWYES","created_at":"2026-05-18T12:25:57Z"},{"alias_kind":"pith_short_8","alias_value":"GSIHJB5S","created_at":"2026-05-18T12:25:57Z"}],"graph_snapshots":[{"event_id":"sha256:975b2d22b12e17ffceae4937d86695530e8dfb8e615119f532521183db3be852","target":"graph","created_at":"2026-05-18T02:15:12Z","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":"Any bipartite quantum state has quasi-probability representations in terms of separable states. For entangled states these quasi-probabilities necessarily exhibit negativities. Based on the general structure of composite quantum states, one may reconstruct such quasi-propabilities from experimental data. Because of ambiguity, the quasi-probabilities obtained by the bare reconstruction are insufficient to identify entanglement. An optimization procedure is introduced to derive quasi-probabilities with a minimal amount of negativity. Negativities of optimized quasi-probabilities unambiguously pr","authors_text":"J. Sperling, W. Vogel","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2008-11-27T12:48:06Z","title":"Representation of entanglement by negative quasi-probabilities"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0811.4527","kind":"arxiv","version":3},"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":"sha256:798ccf2779f690b1c1c43141b0cc190c3b9577b00703019fac957784a45de5ae","target":"record","created_at":"2026-05-18T02:15:12Z","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":"9932b9dcf1af38b8d8315153b0a6112448e272d683886295401bc235dad91342","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2008-11-27T12:48:06Z","title_canon_sha256":"7d0b8cb733263ca7815f671d83d9ed0b4be3c60c87bb9a3d0bc89e08927ad81e"},"schema_version":"1.0","source":{"id":"0811.4527","kind":"arxiv","version":3}},"canonical_sha256":"34907487b279af8b60920eaf12424e83081dcad303cc1cc7cffe9485ef38e0c1","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"34907487b279af8b60920eaf12424e83081dcad303cc1cc7cffe9485ef38e0c1","first_computed_at":"2026-05-18T02:15:12.847274Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:15:12.847274Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"sqBtle00qEkQlS1f+0lRIqHWnmIK9VpnXIOvECxpA6EsZt7FM/wA+tAzBA6VE22eAhcEwshWJmQojsSIHyNSAw==","signature_status":"signed_v1","signed_at":"2026-05-18T02:15:12.848044Z","signed_message":"canonical_sha256_bytes"},"source_id":"0811.4527","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:798ccf2779f690b1c1c43141b0cc190c3b9577b00703019fac957784a45de5ae","sha256:975b2d22b12e17ffceae4937d86695530e8dfb8e615119f532521183db3be852"],"state_sha256":"1a23994686b1485c8f65e8d52956c42c6b82c1e181b10789b9b9f98a725bd363"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"cCceX5v5wZ6stgnajJk5zPxwD7iIPnzqRSvoCkghqSXAIG3Z6WILcEW3bGrZQVGXQeRrPBmKEKi/Q77rE8YeCg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-02T11:24:37.552270Z","bundle_sha256":"7a0c40e7bc7570e6e4a090eb879d1c9cb3b82ead003298407589d34252a9d677"}}