{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2026:27OXZUD2HCDQ5LMDZIOK4DY7JC","short_pith_number":"pith:27OXZUD2","schema_version":"1.0","canonical_sha256":"d7dd7cd07a38870ead83ca1cae0f1f488a09e113910bf5edeb9ab4f49d71401a","source":{"kind":"arxiv","id":"2607.15617","version":1},"attestation_state":"computed","paper":{"title":"Classical codes violate the conjectured square-root bound for quantum random access codes","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["cs.IT","math.IT"],"primary_cat":"quant-ph","authors_text":"Kangqiao Liu","submitted_at":"2026-07-17T04:31:15Z","abstract_excerpt":"We consider whether every quantum random access code (QRAC) with density-operator encodings and arbitrary decoding measurements obeys the conjectured bound $p\\leq(1+\\sqrt{m/n})/2$, where $n$ classical bits are encoded into $m$ qubits and $p$ is the worst-case success probability. We find that classical random access codes with private randomness, which form a subclass of this QRAC model, violate the bound. We embed these classical codes as QRACs with diagonal encoding states and commuting decoding measurements, and construct pure-state realizations with identical decoding statistics. The achie"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"2607.15617","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2026-07-17T04:31:15Z","cross_cats_sorted":["cs.IT","math.IT"],"title_canon_sha256":"ffeb7ddbf48a56d592f3baa658ab5a9d51ff6b044f03a765021c89071149c62b","abstract_canon_sha256":"e716d6f635ecbec01c5270e320c83b634713290fe5d9f0ac8c175ea36388983e"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-20T01:19:00.484958Z","signature_b64":"mKY+CBgBmJRaA5NURmXWwPZLmC529tKPQWO4ZswJ9bS3zFPri0UG4Fv9dpn6SuVgpheLLVpAnfL6zf9o+q8hBA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"d7dd7cd07a38870ead83ca1cae0f1f488a09e113910bf5edeb9ab4f49d71401a","last_reissued_at":"2026-07-20T01:19:00.484040Z","signature_status":"signed_v1","first_computed_at":"2026-07-20T01:19:00.484040Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Classical codes violate the conjectured square-root bound for quantum random access codes","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["cs.IT","math.IT"],"primary_cat":"quant-ph","authors_text":"Kangqiao Liu","submitted_at":"2026-07-17T04:31:15Z","abstract_excerpt":"We consider whether every quantum random access code (QRAC) with density-operator encodings and arbitrary decoding measurements obeys the conjectured bound $p\\leq(1+\\sqrt{m/n})/2$, where $n$ classical bits are encoded into $m$ qubits and $p$ is the worst-case success probability. We find that classical random access codes with private randomness, which form a subclass of this QRAC model, violate the bound. We embed these classical codes as QRACs with diagonal encoding states and commuting decoding measurements, and construct pure-state realizations with identical decoding statistics. The achie"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2607.15617","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2607.15617/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"},"aliases":[{"alias_kind":"arxiv","alias_value":"2607.15617","created_at":"2026-07-20T01:19:00.484494+00:00"},{"alias_kind":"arxiv_version","alias_value":"2607.15617v1","created_at":"2026-07-20T01:19:00.484494+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2607.15617","created_at":"2026-07-20T01:19:00.484494+00:00"},{"alias_kind":"pith_short_12","alias_value":"27OXZUD2HCDQ","created_at":"2026-07-20T01:19:00.484494+00:00"},{"alias_kind":"pith_short_16","alias_value":"27OXZUD2HCDQ5LMD","created_at":"2026-07-20T01:19:00.484494+00:00"},{"alias_kind":"pith_short_8","alias_value":"27OXZUD2","created_at":"2026-07-20T01:19:00.484494+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":0,"internal_anchor_count":0,"sample":[]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC","json":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC.json","graph_json":"https://pith.science/api/pith-number/27OXZUD2HCDQ5LMDZIOK4DY7JC/graph.json","events_json":"https://pith.science/api/pith-number/27OXZUD2HCDQ5LMDZIOK4DY7JC/events.json","paper":"https://pith.science/paper/27OXZUD2"},"agent_actions":{"view_html":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC","download_json":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC.json","view_paper":"https://pith.science/paper/27OXZUD2","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2607.15617&json=true","fetch_graph":"https://pith.science/api/pith-number/27OXZUD2HCDQ5LMDZIOK4DY7JC/graph.json","fetch_events":"https://pith.science/api/pith-number/27OXZUD2HCDQ5LMDZIOK4DY7JC/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC/action/timestamp_anchor","attest_storage":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC/action/storage_attestation","attest_author":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC/action/author_attestation","sign_citation":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC/action/citation_signature","submit_replication":"https://pith.science/pith/27OXZUD2HCDQ5LMDZIOK4DY7JC/action/replication_record"}},"created_at":"2026-07-20T01:19:00.484494+00:00","updated_at":"2026-07-20T01:19:00.484494+00:00"}