{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2015:6XGOEEJ2PEO2WE6PN2O34V4ORZ","short_pith_number":"pith:6XGOEEJ2","canonical_record":{"source":{"id":"1506.01639","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-06-04T16:26:20Z","cross_cats_sorted":[],"title_canon_sha256":"5ff2d9c66b459130fe2b66cc3591f04356cc3cd27239cf6e26748c08fbc97a43","abstract_canon_sha256":"8bfdf29161da11fa6fdd8e28b4d3b1eb4fc8c20482365d78e177b667a3dbeac8"},"schema_version":"1.0"},"canonical_sha256":"f5cce2113a791dab13cf6e9dbe578e8e7193bc80d3d2a76d2478efe2bdad67bd","source":{"kind":"arxiv","id":"1506.01639","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1506.01639","created_at":"2026-05-18T01:21:55Z"},{"alias_kind":"arxiv_version","alias_value":"1506.01639v3","created_at":"2026-05-18T01:21:55Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1506.01639","created_at":"2026-05-18T01:21:55Z"},{"alias_kind":"pith_short_12","alias_value":"6XGOEEJ2PEO2","created_at":"2026-05-18T12:29:07Z"},{"alias_kind":"pith_short_16","alias_value":"6XGOEEJ2PEO2WE6P","created_at":"2026-05-18T12:29:07Z"},{"alias_kind":"pith_short_8","alias_value":"6XGOEEJ2","created_at":"2026-05-18T12:29:07Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2015:6XGOEEJ2PEO2WE6PN2O34V4ORZ","target":"record","payload":{"canonical_record":{"source":{"id":"1506.01639","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-06-04T16:26:20Z","cross_cats_sorted":[],"title_canon_sha256":"5ff2d9c66b459130fe2b66cc3591f04356cc3cd27239cf6e26748c08fbc97a43","abstract_canon_sha256":"8bfdf29161da11fa6fdd8e28b4d3b1eb4fc8c20482365d78e177b667a3dbeac8"},"schema_version":"1.0"},"canonical_sha256":"f5cce2113a791dab13cf6e9dbe578e8e7193bc80d3d2a76d2478efe2bdad67bd","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:21:55.391570Z","signature_b64":"+6+biDpIecnLa5Cq+3kXdwNGc77qEhagHsbCg5EUYtiYCUuZobVlHhJ2++hgYwnl1ku65l7ijtwHRx/mT5QiBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"f5cce2113a791dab13cf6e9dbe578e8e7193bc80d3d2a76d2478efe2bdad67bd","last_reissued_at":"2026-05-18T01:21:55.390973Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:21:55.390973Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1506.01639","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":"2026-05-18T01:21:55Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"js9JXK0/uvBVzltI6iW7oPMWH3479hrJ0GMLX9wTaOANUlOEcT7E86TLJ+xqk2sCCbVn8bBAHfTFB8Jbc5WgBw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-06T09:06:56.764574Z"},"content_sha256":"0565574adc716e0c7c94549b4c045e6d3718f364021e038a8b37dfa6a06a7c75","schema_version":"1.0","event_id":"sha256:0565574adc716e0c7c94549b4c045e6d3718f364021e038a8b37dfa6a06a7c75"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2015:6XGOEEJ2PEO2WE6PN2O34V4ORZ","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Quantum cellular automata without particles","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Asif Shakeel, David A. Meyer","submitted_at":"2015-06-04T16:26:20Z","abstract_excerpt":"Quantum cellular automata (QCA) constitute space and time homogeneous discrete models for quantum field theories (QFTs). Although QFTs are defined without reference to particles, computations are done in terms of Feynman diagrams, which are explicitly interpreted in terms of interacting particles. Similarly, the easiest QCA to construct are quantum lattice gas automata (QLGA). A natural question then is, which QCA are not QLGA? Here we construct a non-trivial example of such a QCA; it provides a simple model in $1+1$ dimensions with no particle interpretation at the scale where the QCA dynamic"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1506.01639","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":"2026-05-18T01:21:55Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"OnTigx+Iia85Q3E6yeN0cO2GkAhfqZwBi7hBAkuMcySquy+8xsAD/IrUUV6Bhf50to9FVmX0TdRQo1GuReIdBg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-06T09:06:56.764946Z"},"content_sha256":"1645e339ca1309ff5adc0c45aea3d567ed82f639e71d98f6a4aec65451140f6e","schema_version":"1.0","event_id":"sha256:1645e339ca1309ff5adc0c45aea3d567ed82f639e71d98f6a4aec65451140f6e"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/6XGOEEJ2PEO2WE6PN2O34V4ORZ/bundle.json","state_url":"https://pith.science/pith/6XGOEEJ2PEO2WE6PN2O34V4ORZ/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/6XGOEEJ2PEO2WE6PN2O34V4ORZ/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":"2026-06-06T09:06:56Z","links":{"resolver":"https://pith.science/pith/6XGOEEJ2PEO2WE6PN2O34V4ORZ","bundle":"https://pith.science/pith/6XGOEEJ2PEO2WE6PN2O34V4ORZ/bundle.json","state":"https://pith.science/pith/6XGOEEJ2PEO2WE6PN2O34V4ORZ/state.json","well_known_bundle":"https://pith.science/.well-known/pith/6XGOEEJ2PEO2WE6PN2O34V4ORZ/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2015:6XGOEEJ2PEO2WE6PN2O34V4ORZ","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":"8bfdf29161da11fa6fdd8e28b4d3b1eb4fc8c20482365d78e177b667a3dbeac8","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-06-04T16:26:20Z","title_canon_sha256":"5ff2d9c66b459130fe2b66cc3591f04356cc3cd27239cf6e26748c08fbc97a43"},"schema_version":"1.0","source":{"id":"1506.01639","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1506.01639","created_at":"2026-05-18T01:21:55Z"},{"alias_kind":"arxiv_version","alias_value":"1506.01639v3","created_at":"2026-05-18T01:21:55Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1506.01639","created_at":"2026-05-18T01:21:55Z"},{"alias_kind":"pith_short_12","alias_value":"6XGOEEJ2PEO2","created_at":"2026-05-18T12:29:07Z"},{"alias_kind":"pith_short_16","alias_value":"6XGOEEJ2PEO2WE6P","created_at":"2026-05-18T12:29:07Z"},{"alias_kind":"pith_short_8","alias_value":"6XGOEEJ2","created_at":"2026-05-18T12:29:07Z"}],"graph_snapshots":[{"event_id":"sha256:1645e339ca1309ff5adc0c45aea3d567ed82f639e71d98f6a4aec65451140f6e","target":"graph","created_at":"2026-05-18T01:21:55Z","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":"Quantum cellular automata (QCA) constitute space and time homogeneous discrete models for quantum field theories (QFTs). Although QFTs are defined without reference to particles, computations are done in terms of Feynman diagrams, which are explicitly interpreted in terms of interacting particles. Similarly, the easiest QCA to construct are quantum lattice gas automata (QLGA). A natural question then is, which QCA are not QLGA? Here we construct a non-trivial example of such a QCA; it provides a simple model in $1+1$ dimensions with no particle interpretation at the scale where the QCA dynamic","authors_text":"Asif Shakeel, David A. Meyer","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-06-04T16:26:20Z","title":"Quantum cellular automata without particles"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1506.01639","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":"sha256:0565574adc716e0c7c94549b4c045e6d3718f364021e038a8b37dfa6a06a7c75","target":"record","created_at":"2026-05-18T01:21:55Z","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":"8bfdf29161da11fa6fdd8e28b4d3b1eb4fc8c20482365d78e177b667a3dbeac8","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-06-04T16:26:20Z","title_canon_sha256":"5ff2d9c66b459130fe2b66cc3591f04356cc3cd27239cf6e26748c08fbc97a43"},"schema_version":"1.0","source":{"id":"1506.01639","kind":"arxiv","version":3}},"canonical_sha256":"f5cce2113a791dab13cf6e9dbe578e8e7193bc80d3d2a76d2478efe2bdad67bd","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"f5cce2113a791dab13cf6e9dbe578e8e7193bc80d3d2a76d2478efe2bdad67bd","first_computed_at":"2026-05-18T01:21:55.390973Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:21:55.390973Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"+6+biDpIecnLa5Cq+3kXdwNGc77qEhagHsbCg5EUYtiYCUuZobVlHhJ2++hgYwnl1ku65l7ijtwHRx/mT5QiBw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:21:55.391570Z","signed_message":"canonical_sha256_bytes"},"source_id":"1506.01639","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:0565574adc716e0c7c94549b4c045e6d3718f364021e038a8b37dfa6a06a7c75","sha256:1645e339ca1309ff5adc0c45aea3d567ed82f639e71d98f6a4aec65451140f6e"],"state_sha256":"198534d52409a7e145e55518bf34de8df8efa3930a6a2f63a12ae133e2049ed3"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"EqhvBYhblGTSEK8NP3D6SQ7n4ch/bHg9z+llZMODEf5plMoQqPJ3wJPEnNYFacuN6Svg7ngDRalfMmoT/BnDDA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-06T09:06:56.767087Z","bundle_sha256":"b28c29c83a302eeeb1f34bed017c5d3ce1b6c05529194d33e38340cb69555c53"}}