{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2020:BNCVGVKBRXMZDFFIM5BKJJNRUK","short_pith_number":"pith:BNCVGVKB","canonical_record":{"source":{"id":"2003.09042","kind":"arxiv","version":3},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2020-03-19T23:03:42Z","cross_cats_sorted":[],"title_canon_sha256":"b3aabf8009afbd0110dce12fcbf2a51915ad2888f0db1600f69df15ea3761a97","abstract_canon_sha256":"51e1a57dcc3a443f328e0ac2ce297ef83a315ff56b38dafedc7fca89b258138d"},"schema_version":"1.0"},"canonical_sha256":"0b455355418dd99194a86742a4a5b1a2a62503a2eaae07780d450a5e0d78ed6c","source":{"kind":"arxiv","id":"2003.09042","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2003.09042","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"arxiv_version","alias_value":"2003.09042v3","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2003.09042","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"pith_short_12","alias_value":"BNCVGVKBRXMZ","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"pith_short_16","alias_value":"BNCVGVKBRXMZDFFI","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"pith_short_8","alias_value":"BNCVGVKB","created_at":"2026-07-05T03:50:33Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2020:BNCVGVKBRXMZDFFIM5BKJJNRUK","target":"record","payload":{"canonical_record":{"source":{"id":"2003.09042","kind":"arxiv","version":3},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2020-03-19T23:03:42Z","cross_cats_sorted":[],"title_canon_sha256":"b3aabf8009afbd0110dce12fcbf2a51915ad2888f0db1600f69df15ea3761a97","abstract_canon_sha256":"51e1a57dcc3a443f328e0ac2ce297ef83a315ff56b38dafedc7fca89b258138d"},"schema_version":"1.0"},"canonical_sha256":"0b455355418dd99194a86742a4a5b1a2a62503a2eaae07780d450a5e0d78ed6c","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T03:50:33.754473Z","signature_b64":"KwloNjjNvyr7YBM0RIeqDy9FlWhrjaV1dMqslS7zuhZgJRtWcKiuA4jxucpnhSCsC5ET5a2HdvyfVBzr3kvUCA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"0b455355418dd99194a86742a4a5b1a2a62503a2eaae07780d450a5e0d78ed6c","last_reissued_at":"2026-07-05T03:50:33.753989Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T03:50:33.753989Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2003.09042","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":"2026-07-05T03:50:33Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"rgLxaNxyYq+eyGk3otWvN/L/tJmL3W/5GCVr3FU4BojHGHmPM3fPfLQ2W3PvMZ3nKnoh7mnuTEAVULrLOgWtAw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-10T21:04:30.551339Z"},"content_sha256":"5346980b1ac7eec3dc8035fa2b6d969b9ec935322d8a667b2c6c025ed1971e87","schema_version":"1.0","event_id":"sha256:5346980b1ac7eec3dc8035fa2b6d969b9ec935322d8a667b2c6c025ed1971e87"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2020:BNCVGVKBRXMZDFFIM5BKJJNRUK","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Time Observables in a Timeless Universe","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Augusto Smerzi, Tommaso Favalli","submitted_at":"2020-03-19T23:03:42Z","abstract_excerpt":"Time in quantum mechanics is peculiar: it is an observable that cannot be associated to an Hermitian operator. As a consequence it is impossible to explain dynamics in an isolated system without invoking an external classical clock, a fact that becomes particularly problematic in the context of quantum gravity. An unconventional solution was pioneered by Page and Wootters (PaW) in 1983. PaW showed that dynamics can be an emergent property of the entanglement between two subsystems of a static Universe. In this work we first investigate the possibility to introduce in this framework a Hermitian"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2003.09042","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2003.09042/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":"2026-07-05T03:50:33Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"6c550laJiAsZNNLcJ14emVxcfr/g/2EE9NhyrQR1ZV/QuBGw+2IhX6B33ufevT9rDb9TZ6ycX6nNKblCbHiJAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-10T21:04:30.552279Z"},"content_sha256":"e3bcd0e98df217034fa07ec4e3df51757a75346c9b396ac780005fc7a80a2a09","schema_version":"1.0","event_id":"sha256:e3bcd0e98df217034fa07ec4e3df51757a75346c9b396ac780005fc7a80a2a09"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/BNCVGVKBRXMZDFFIM5BKJJNRUK/bundle.json","state_url":"https://pith.science/pith/BNCVGVKBRXMZDFFIM5BKJJNRUK/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/BNCVGVKBRXMZDFFIM5BKJJNRUK/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":"2026-08-10T21:04:30Z","links":{"resolver":"https://pith.science/pith/BNCVGVKBRXMZDFFIM5BKJJNRUK","bundle":"https://pith.science/pith/BNCVGVKBRXMZDFFIM5BKJJNRUK/bundle.json","state":"https://pith.science/pith/BNCVGVKBRXMZDFFIM5BKJJNRUK/state.json","well_known_bundle":"https://pith.science/.well-known/pith/BNCVGVKBRXMZDFFIM5BKJJNRUK/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2020:BNCVGVKBRXMZDFFIM5BKJJNRUK","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":"51e1a57dcc3a443f328e0ac2ce297ef83a315ff56b38dafedc7fca89b258138d","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2020-03-19T23:03:42Z","title_canon_sha256":"b3aabf8009afbd0110dce12fcbf2a51915ad2888f0db1600f69df15ea3761a97"},"schema_version":"1.0","source":{"id":"2003.09042","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2003.09042","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"arxiv_version","alias_value":"2003.09042v3","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2003.09042","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"pith_short_12","alias_value":"BNCVGVKBRXMZ","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"pith_short_16","alias_value":"BNCVGVKBRXMZDFFI","created_at":"2026-07-05T03:50:33Z"},{"alias_kind":"pith_short_8","alias_value":"BNCVGVKB","created_at":"2026-07-05T03:50:33Z"}],"graph_snapshots":[{"event_id":"sha256:e3bcd0e98df217034fa07ec4e3df51757a75346c9b396ac780005fc7a80a2a09","target":"graph","created_at":"2026-07-05T03:50:33Z","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/2003.09042/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Time in quantum mechanics is peculiar: it is an observable that cannot be associated to an Hermitian operator. As a consequence it is impossible to explain dynamics in an isolated system without invoking an external classical clock, a fact that becomes particularly problematic in the context of quantum gravity. An unconventional solution was pioneered by Page and Wootters (PaW) in 1983. PaW showed that dynamics can be an emergent property of the entanglement between two subsystems of a static Universe. In this work we first investigate the possibility to introduce in this framework a Hermitian","authors_text":"Augusto Smerzi, Tommaso Favalli","cross_cats":[],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2020-03-19T23:03:42Z","title":"Time Observables in a Timeless Universe"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2003.09042","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":"sha256:5346980b1ac7eec3dc8035fa2b6d969b9ec935322d8a667b2c6c025ed1971e87","target":"record","created_at":"2026-07-05T03:50:33Z","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":"51e1a57dcc3a443f328e0ac2ce297ef83a315ff56b38dafedc7fca89b258138d","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2020-03-19T23:03:42Z","title_canon_sha256":"b3aabf8009afbd0110dce12fcbf2a51915ad2888f0db1600f69df15ea3761a97"},"schema_version":"1.0","source":{"id":"2003.09042","kind":"arxiv","version":3}},"canonical_sha256":"0b455355418dd99194a86742a4a5b1a2a62503a2eaae07780d450a5e0d78ed6c","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"0b455355418dd99194a86742a4a5b1a2a62503a2eaae07780d450a5e0d78ed6c","first_computed_at":"2026-07-05T03:50:33.753989Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T03:50:33.753989Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"KwloNjjNvyr7YBM0RIeqDy9FlWhrjaV1dMqslS7zuhZgJRtWcKiuA4jxucpnhSCsC5ET5a2HdvyfVBzr3kvUCA==","signature_status":"signed_v1","signed_at":"2026-07-05T03:50:33.754473Z","signed_message":"canonical_sha256_bytes"},"source_id":"2003.09042","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:5346980b1ac7eec3dc8035fa2b6d969b9ec935322d8a667b2c6c025ed1971e87","sha256:e3bcd0e98df217034fa07ec4e3df51757a75346c9b396ac780005fc7a80a2a09"],"state_sha256":"827c489793d014a22a7be95ad2baf7dd6d1d2ab2abd0ea1aa5c9a2a07df3de35"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"LX1gNAqaRDCp/sAocPwA+mssFrDex/hGMo83pOVqx9QIjb6WNnZCDHhR1gHisNdzASQtHl8+jZGXneMWqzobBQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-10T21:04:30.577425Z","bundle_sha256":"b00f0d052e0a4cf9baa8656346f4a87ba00953257d7e5ed8eaef1f06f860c3d4"}}