{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:UAQXUABTY4ORK73CLKIZWK3HEM","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":"aa8b275ad4036de3dba93b53eec7f5ce25d4ae9b123dcec1b2b7b6468e36aad8","cross_cats_sorted":["gr-qc","hep-th"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2019-12-12T19:00:01Z","title_canon_sha256":"b863711602084c24be08a5a05c8324e14fc56e57bd6baf44566264af0463294d"},"schema_version":"1.0","source":{"id":"1912.06141","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1912.06141","created_at":"2026-07-05T03:22:56Z"},{"alias_kind":"arxiv_version","alias_value":"1912.06141v3","created_at":"2026-07-05T03:22:56Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1912.06141","created_at":"2026-07-05T03:22:56Z"},{"alias_kind":"pith_short_12","alias_value":"UAQXUABTY4OR","created_at":"2026-07-05T03:22:56Z"},{"alias_kind":"pith_short_16","alias_value":"UAQXUABTY4ORK73C","created_at":"2026-07-05T03:22:56Z"},{"alias_kind":"pith_short_8","alias_value":"UAQXUABT","created_at":"2026-07-05T03:22:56Z"}],"graph_snapshots":[{"event_id":"sha256:900399bead906e495bf211fe91260e707dd32d2a223886d87d1c84e03ca119bd","target":"graph","created_at":"2026-07-05T03:22:56Z","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/1912.06141/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"It is by now well-recognised that the na\\\"ive application of the projection postulate on composite quantum systems can induce signalling between their constituent components, indicative of a breakdown of causality in a relativistic spacetime context. Here we introduce a necessary and sufficient condition for an ideal measurement of an observable to be non-signalling. As well as being particularly simple, it generalises previous no-signalling conditions in that it allows for degeneracies and can be applied to all bounded self-adjoint operators. The condition is used to establish that arbitrary ","authors_text":"Graham Kells, Ian Jubb, Leron Borsten","cross_cats":["gr-qc","hep-th"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2019-12-12T19:00:01Z","title":"Impossible measurements revisited"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1912.06141","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":"sha256:60b45953eb07a5e8387f242eaa8fb801b161b8127b8cf2b094a691a927754cf3","target":"record","created_at":"2026-07-05T03:22:56Z","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":"aa8b275ad4036de3dba93b53eec7f5ce25d4ae9b123dcec1b2b7b6468e36aad8","cross_cats_sorted":["gr-qc","hep-th"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2019-12-12T19:00:01Z","title_canon_sha256":"b863711602084c24be08a5a05c8324e14fc56e57bd6baf44566264af0463294d"},"schema_version":"1.0","source":{"id":"1912.06141","kind":"arxiv","version":3}},"canonical_sha256":"a0217a0033c71d157f625a919b2b67230db142cbf1c91503b27e37be87d4ade5","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"a0217a0033c71d157f625a919b2b67230db142cbf1c91503b27e37be87d4ade5","first_computed_at":"2026-07-05T03:22:56.822879Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T03:22:56.822879Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"7J9Ptuxec8JuhL4be/Upgs+l3PBlyOIzd8LLfiXuyfmqSF1IfzNP0G0+mveqVl1UgArdIniSVRS20siH190kDg==","signature_status":"signed_v1","signed_at":"2026-07-05T03:22:56.823287Z","signed_message":"canonical_sha256_bytes"},"source_id":"1912.06141","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:60b45953eb07a5e8387f242eaa8fb801b161b8127b8cf2b094a691a927754cf3","sha256:900399bead906e495bf211fe91260e707dd32d2a223886d87d1c84e03ca119bd"],"state_sha256":"94c6f0517f4ba30dfc90cda4ba00b9ae2efbff9fa4ae274efdb2d5639173d9bb"}