{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2013:TB6JOLQMV4264MB2CRWQLBQ6QL","short_pith_number":"pith:TB6JOLQM","canonical_record":{"source":{"id":"1304.6879","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2013-04-25T11:31:37Z","cross_cats_sorted":[],"title_canon_sha256":"c5deb3e244ec5d8f137605860ba33698fa092cbe642c31568779183561da63ea","abstract_canon_sha256":"0ae9b26c4b70457303a25aadfc33b7dfa752ee452cfa5e5c69b52547671e2d9c"},"schema_version":"1.0"},"canonical_sha256":"987c972e0caf35ee303a146d05861e82d0d6587f71c729ef4ec658035c427fdf","source":{"kind":"arxiv","id":"1304.6879","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1304.6879","created_at":"2026-05-18T03:01:24Z"},{"alias_kind":"arxiv_version","alias_value":"1304.6879v2","created_at":"2026-05-18T03:01:24Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1304.6879","created_at":"2026-05-18T03:01:24Z"},{"alias_kind":"pith_short_12","alias_value":"TB6JOLQMV426","created_at":"2026-05-18T12:27:59Z"},{"alias_kind":"pith_short_16","alias_value":"TB6JOLQMV4264MB2","created_at":"2026-05-18T12:27:59Z"},{"alias_kind":"pith_short_8","alias_value":"TB6JOLQM","created_at":"2026-05-18T12:27:59Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2013:TB6JOLQMV4264MB2CRWQLBQ6QL","target":"record","payload":{"canonical_record":{"source":{"id":"1304.6879","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2013-04-25T11:31:37Z","cross_cats_sorted":[],"title_canon_sha256":"c5deb3e244ec5d8f137605860ba33698fa092cbe642c31568779183561da63ea","abstract_canon_sha256":"0ae9b26c4b70457303a25aadfc33b7dfa752ee452cfa5e5c69b52547671e2d9c"},"schema_version":"1.0"},"canonical_sha256":"987c972e0caf35ee303a146d05861e82d0d6587f71c729ef4ec658035c427fdf","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T03:01:24.324626Z","signature_b64":"7DsuPJD27UTJd97qVnpaA6FhVKIwA0oAY0gVMD6e8WdapMIZuk3753bf3+qpXaoxq43Xlc7Sl9Hwqtyd7XmHAg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"987c972e0caf35ee303a146d05861e82d0d6587f71c729ef4ec658035c427fdf","last_reissued_at":"2026-05-18T03:01:24.323955Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T03:01:24.323955Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1304.6879","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":"2026-05-18T03:01:24Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"erY6yoNzsa9ISr4GhBCfdJGw1HBu3sMbjnpmXUBM86bZPI58prHKBoXEXrrNSZ++d06qGF+YyqOBnyxVvPkHAQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-06T14:10:01.229081Z"},"content_sha256":"8797dea658b588a33e8c6f6ed21195e084d39d75514d1a70b862c7467a840e30","schema_version":"1.0","event_id":"sha256:8797dea658b588a33e8c6f6ed21195e084d39d75514d1a70b862c7467a840e30"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2013:TB6JOLQMV4264MB2CRWQLBQ6QL","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Toward computability of trace distance discord","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"F. Ciccarello, T. Tufarelli, V. Giovannetti","submitted_at":"2013-04-25T11:31:37Z","abstract_excerpt":"It is known that a reliable geometric quantifier of discord-like correlations can be built by employing the so-called trace distance. This is used to measure how far the state under investigation is from the closest \"classical-quantum\" one. To date, the explicit calculation of this indicator for two qubits was accomplished only for states such that the reduced density matrix of the measured party is maximally mixed, a class that includes Bell-diagonal states. Here, we first reduce the required optimization for a general two-qubit state to the minimization of an explicit two-variable function. "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1304.6879","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":""},"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":"2026-05-18T03:01:24Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"1lIBC23zQM480Mb6xu4cOk724rGAW8t/gKjRUgtoB3hdwiL4vH5HBLTf8WTzby1ueHysK37vyzKof2hlNhBOAQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-06T14:10:01.229575Z"},"content_sha256":"e23a65e7b9501821a1b23cb880f48e4ac9ae8660dc4c88d2c00b914fc52c9a1b","schema_version":"1.0","event_id":"sha256:e23a65e7b9501821a1b23cb880f48e4ac9ae8660dc4c88d2c00b914fc52c9a1b"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/TB6JOLQMV4264MB2CRWQLBQ6QL/bundle.json","state_url":"https://pith.science/pith/TB6JOLQMV4264MB2CRWQLBQ6QL/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/TB6JOLQMV4264MB2CRWQLBQ6QL/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":"2026-06-06T14:10:01Z","links":{"resolver":"https://pith.science/pith/TB6JOLQMV4264MB2CRWQLBQ6QL","bundle":"https://pith.science/pith/TB6JOLQMV4264MB2CRWQLBQ6QL/bundle.json","state":"https://pith.science/pith/TB6JOLQMV4264MB2CRWQLBQ6QL/state.json","well_known_bundle":"https://pith.science/.well-known/pith/TB6JOLQMV4264MB2CRWQLBQ6QL/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:TB6JOLQMV4264MB2CRWQLBQ6QL","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":"0ae9b26c4b70457303a25aadfc33b7dfa752ee452cfa5e5c69b52547671e2d9c","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2013-04-25T11:31:37Z","title_canon_sha256":"c5deb3e244ec5d8f137605860ba33698fa092cbe642c31568779183561da63ea"},"schema_version":"1.0","source":{"id":"1304.6879","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1304.6879","created_at":"2026-05-18T03:01:24Z"},{"alias_kind":"arxiv_version","alias_value":"1304.6879v2","created_at":"2026-05-18T03:01:24Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1304.6879","created_at":"2026-05-18T03:01:24Z"},{"alias_kind":"pith_short_12","alias_value":"TB6JOLQMV426","created_at":"2026-05-18T12:27:59Z"},{"alias_kind":"pith_short_16","alias_value":"TB6JOLQMV4264MB2","created_at":"2026-05-18T12:27:59Z"},{"alias_kind":"pith_short_8","alias_value":"TB6JOLQM","created_at":"2026-05-18T12:27:59Z"}],"graph_snapshots":[{"event_id":"sha256:e23a65e7b9501821a1b23cb880f48e4ac9ae8660dc4c88d2c00b914fc52c9a1b","target":"graph","created_at":"2026-05-18T03:01:24Z","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":"It is known that a reliable geometric quantifier of discord-like correlations can be built by employing the so-called trace distance. This is used to measure how far the state under investigation is from the closest \"classical-quantum\" one. To date, the explicit calculation of this indicator for two qubits was accomplished only for states such that the reduced density matrix of the measured party is maximally mixed, a class that includes Bell-diagonal states. Here, we first reduce the required optimization for a general two-qubit state to the minimization of an explicit two-variable function. ","authors_text":"F. Ciccarello, T. Tufarelli, V. Giovannetti","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2013-04-25T11:31:37Z","title":"Toward computability of trace distance discord"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1304.6879","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":"sha256:8797dea658b588a33e8c6f6ed21195e084d39d75514d1a70b862c7467a840e30","target":"record","created_at":"2026-05-18T03:01:24Z","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":"0ae9b26c4b70457303a25aadfc33b7dfa752ee452cfa5e5c69b52547671e2d9c","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2013-04-25T11:31:37Z","title_canon_sha256":"c5deb3e244ec5d8f137605860ba33698fa092cbe642c31568779183561da63ea"},"schema_version":"1.0","source":{"id":"1304.6879","kind":"arxiv","version":2}},"canonical_sha256":"987c972e0caf35ee303a146d05861e82d0d6587f71c729ef4ec658035c427fdf","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"987c972e0caf35ee303a146d05861e82d0d6587f71c729ef4ec658035c427fdf","first_computed_at":"2026-05-18T03:01:24.323955Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:01:24.323955Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"7DsuPJD27UTJd97qVnpaA6FhVKIwA0oAY0gVMD6e8WdapMIZuk3753bf3+qpXaoxq43Xlc7Sl9Hwqtyd7XmHAg==","signature_status":"signed_v1","signed_at":"2026-05-18T03:01:24.324626Z","signed_message":"canonical_sha256_bytes"},"source_id":"1304.6879","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:8797dea658b588a33e8c6f6ed21195e084d39d75514d1a70b862c7467a840e30","sha256:e23a65e7b9501821a1b23cb880f48e4ac9ae8660dc4c88d2c00b914fc52c9a1b"],"state_sha256":"f0d86685c6b2cc003f3977b33e3ebab3998579afb0490bd1bd062cd30499a69c"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"9v9sCbD1+SYsLIxodL0igQtveSIKJsPlfryIiA1sXBmE/vhqCJnfzg4drZIknMVJ/ZE/MPtPP89XKtcsse5nDw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-06T14:10:01.233976Z","bundle_sha256":"79dbcab8131b64d1f4d069442d69841f62f116b708e515fdaecc435de413851b"}}