{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2024:YRDOQKNNFZRUSGIF3ZJWFWGDNJ","short_pith_number":"pith:YRDOQKNN","canonical_record":{"source":{"id":"2407.21760","kind":"arxiv","version":2},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2024-07-31T17:29:15Z","cross_cats_sorted":[],"title_canon_sha256":"a3d4996c513bdad0dacbb58119fc90c0655db09a1ed29cb8cd86f6d76c901997","abstract_canon_sha256":"7c73e2a207d53c703e7a1f656c897aaf47d07c270c5c031408efa85a3df13266"},"schema_version":"1.0"},"canonical_sha256":"c446e829ad2e63491905de5362d8c36a70820078027906de65d9c40c12ec6c16","source":{"kind":"arxiv","id":"2407.21760","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2407.21760","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"arxiv_version","alias_value":"2407.21760v2","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2407.21760","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"pith_short_12","alias_value":"YRDOQKNNFZRU","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"pith_short_16","alias_value":"YRDOQKNNFZRUSGIF","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"pith_short_8","alias_value":"YRDOQKNN","created_at":"2026-07-05T11:35:29Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2024:YRDOQKNNFZRUSGIF3ZJWFWGDNJ","target":"record","payload":{"canonical_record":{"source":{"id":"2407.21760","kind":"arxiv","version":2},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2024-07-31T17:29:15Z","cross_cats_sorted":[],"title_canon_sha256":"a3d4996c513bdad0dacbb58119fc90c0655db09a1ed29cb8cd86f6d76c901997","abstract_canon_sha256":"7c73e2a207d53c703e7a1f656c897aaf47d07c270c5c031408efa85a3df13266"},"schema_version":"1.0"},"canonical_sha256":"c446e829ad2e63491905de5362d8c36a70820078027906de65d9c40c12ec6c16","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T11:35:29.706021Z","signature_b64":"kSFV6T8oDQxWQTohqQZ10s5sr47o2UPrR7NZl2hs2vacBau7W+iJrsxKA8jsNILHDADsY6SSEKgs7hC8sKVUDQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"c446e829ad2e63491905de5362d8c36a70820078027906de65d9c40c12ec6c16","last_reissued_at":"2026-07-05T11:35:29.705598Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T11:35:29.705598Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2407.21760","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":"2026-07-05T11:35:29Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"GSUwBB3eNev3nmpON6T2E5kRuJmJzx52VxZpp3gxlv5GWJPd/rK+chIzGagnvQtaAhD0AGAswXlHkjIac/z4CQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-11T20:14:48.293235Z"},"content_sha256":"54d3c9a90aef9e890eafcc815e7b781b2d1676f301794728eabde85ac49564a3","schema_version":"1.0","event_id":"sha256:54d3c9a90aef9e890eafcc815e7b781b2d1676f301794728eabde85ac49564a3"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2024:YRDOQKNNFZRUSGIF3ZJWFWGDNJ","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"No-Go Theorems for Universal Entanglement Purification","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Allen Zang, Eric Chitambar, Martin Suchara, Tian Zhong, Xinan Chen","submitted_at":"2024-07-31T17:29:15Z","abstract_excerpt":"An entanglement purification protocol (EPP) aims to transform multiple noisy entangled states into a single entangled state with higher fidelity. In this work we consider EPPs that always yield an output fidelity no worse than each of the original noisy states, a property we call universality. We prove there is no $n$-to-1 EPP implementable by local operations and classical communication that is universal for all two-qubit entangled states, whereas such an EPP is possible using more general positive partial transpose-preserving (PPT) operations. We also show that universality is not possible b"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2407.21760","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2407.21760/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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":"2026-07-05T11:35:29Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"mv6wO1BRWbS7ziisEr5fqVPjTqrcbzoS1KgUiAZE1v49K8Ti9753oNLAMnN1SAd2Yl2wZAAbl2fULE12FJNHCA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-11T20:14:48.293560Z"},"content_sha256":"327db4a65c539e6aee2da39da1c512f06db60b791727906367acd4ebb786bc3b","schema_version":"1.0","event_id":"sha256:327db4a65c539e6aee2da39da1c512f06db60b791727906367acd4ebb786bc3b"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/YRDOQKNNFZRUSGIF3ZJWFWGDNJ/bundle.json","state_url":"https://pith.science/pith/YRDOQKNNFZRUSGIF3ZJWFWGDNJ/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/YRDOQKNNFZRUSGIF3ZJWFWGDNJ/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":"2026-08-11T20:14:48Z","links":{"resolver":"https://pith.science/pith/YRDOQKNNFZRUSGIF3ZJWFWGDNJ","bundle":"https://pith.science/pith/YRDOQKNNFZRUSGIF3ZJWFWGDNJ/bundle.json","state":"https://pith.science/pith/YRDOQKNNFZRUSGIF3ZJWFWGDNJ/state.json","well_known_bundle":"https://pith.science/.well-known/pith/YRDOQKNNFZRUSGIF3ZJWFWGDNJ/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2024:YRDOQKNNFZRUSGIF3ZJWFWGDNJ","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":"7c73e2a207d53c703e7a1f656c897aaf47d07c270c5c031408efa85a3df13266","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2024-07-31T17:29:15Z","title_canon_sha256":"a3d4996c513bdad0dacbb58119fc90c0655db09a1ed29cb8cd86f6d76c901997"},"schema_version":"1.0","source":{"id":"2407.21760","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2407.21760","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"arxiv_version","alias_value":"2407.21760v2","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2407.21760","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"pith_short_12","alias_value":"YRDOQKNNFZRU","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"pith_short_16","alias_value":"YRDOQKNNFZRUSGIF","created_at":"2026-07-05T11:35:29Z"},{"alias_kind":"pith_short_8","alias_value":"YRDOQKNN","created_at":"2026-07-05T11:35:29Z"}],"graph_snapshots":[{"event_id":"sha256:327db4a65c539e6aee2da39da1c512f06db60b791727906367acd4ebb786bc3b","target":"graph","created_at":"2026-07-05T11:35:29Z","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"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2407.21760/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"An entanglement purification protocol (EPP) aims to transform multiple noisy entangled states into a single entangled state with higher fidelity. In this work we consider EPPs that always yield an output fidelity no worse than each of the original noisy states, a property we call universality. We prove there is no $n$-to-1 EPP implementable by local operations and classical communication that is universal for all two-qubit entangled states, whereas such an EPP is possible using more general positive partial transpose-preserving (PPT) operations. We also show that universality is not possible b","authors_text":"Allen Zang, Eric Chitambar, Martin Suchara, Tian Zhong, Xinan Chen","cross_cats":[],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2024-07-31T17:29:15Z","title":"No-Go Theorems for Universal Entanglement Purification"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2407.21760","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":"sha256:54d3c9a90aef9e890eafcc815e7b781b2d1676f301794728eabde85ac49564a3","target":"record","created_at":"2026-07-05T11:35:29Z","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":"7c73e2a207d53c703e7a1f656c897aaf47d07c270c5c031408efa85a3df13266","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2024-07-31T17:29:15Z","title_canon_sha256":"a3d4996c513bdad0dacbb58119fc90c0655db09a1ed29cb8cd86f6d76c901997"},"schema_version":"1.0","source":{"id":"2407.21760","kind":"arxiv","version":2}},"canonical_sha256":"c446e829ad2e63491905de5362d8c36a70820078027906de65d9c40c12ec6c16","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"c446e829ad2e63491905de5362d8c36a70820078027906de65d9c40c12ec6c16","first_computed_at":"2026-07-05T11:35:29.705598Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T11:35:29.705598Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"kSFV6T8oDQxWQTohqQZ10s5sr47o2UPrR7NZl2hs2vacBau7W+iJrsxKA8jsNILHDADsY6SSEKgs7hC8sKVUDQ==","signature_status":"signed_v1","signed_at":"2026-07-05T11:35:29.706021Z","signed_message":"canonical_sha256_bytes"},"source_id":"2407.21760","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:54d3c9a90aef9e890eafcc815e7b781b2d1676f301794728eabde85ac49564a3","sha256:327db4a65c539e6aee2da39da1c512f06db60b791727906367acd4ebb786bc3b"],"state_sha256":"1a8683e160785a5b8d9c4becbf9ec6bfac4647afae66a6bb88881329dc40cc09"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ksme/2Teagq1FaU/7hAe4sq+PMdmWwlqrrKZw7yboGpocBqetmoI2za9WpxOuxGxNLicc2/WFNDur7fv4d/4CA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-11T20:14:48.296175Z","bundle_sha256":"fe482a626da99533ae321d405bcb3fd44b975acd72b24d82b0cbeeefcc4fea94"}}