{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:O7EE5JVKHUUAZF5NI4HCEEWSWN","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":"e8da4546d6de25a08246f222085a823b90c70c8fa0bb9e62e4e76bfb52ee886f","cross_cats_sorted":["hep-th"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-08-30T18:04:17Z","title_canon_sha256":"b870bfb11b9d92c36e2bfacb46a731ee8057353571664f1d7d1bfca4a60d2e70"},"schema_version":"1.0","source":{"id":"1808.10469","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1808.10469","created_at":"2026-05-18T00:04:20Z"},{"alias_kind":"arxiv_version","alias_value":"1808.10469v2","created_at":"2026-05-18T00:04:20Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1808.10469","created_at":"2026-05-18T00:04:20Z"},{"alias_kind":"pith_short_12","alias_value":"O7EE5JVKHUUA","created_at":"2026-05-18T12:32:43Z"},{"alias_kind":"pith_short_16","alias_value":"O7EE5JVKHUUAZF5N","created_at":"2026-05-18T12:32:43Z"},{"alias_kind":"pith_short_8","alias_value":"O7EE5JVK","created_at":"2026-05-18T12:32:43Z"}],"graph_snapshots":[{"event_id":"sha256:48dcf6accee6d82f6803a9ca36c3bdab45261a47be01d8acf7b1a2e8bba9c62d","target":"graph","created_at":"2026-05-18T00:04:20Z","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":"While the equations of general relativity take the same form in any coordinate system, choosing a suitable set of coordinates is essential in any practical application. This poses a challenge in background-independent quantum gravity, where coordinates are not a priori available and need to be reconstructed from physical degrees of freedom. We review the general idea of coupling free scalar fields to gravity and using these scalars as a \"matter reference frame.\" The resulting coordinate system is harmonic, i.e. it satisfies harmonic (de Donder) gauge. We then show how to introduce such matter ","authors_text":"Steffen Gielen","cross_cats":["hep-th"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-08-30T18:04:17Z","title":"Group field theory and its cosmology in a matter reference frame"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1808.10469","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":"sha256:915c9eed0cf8b6a802f0f5e988b7d8cc66fc74f76ed3ea57467eee53bae5d595","target":"record","created_at":"2026-05-18T00:04:20Z","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":"e8da4546d6de25a08246f222085a823b90c70c8fa0bb9e62e4e76bfb52ee886f","cross_cats_sorted":["hep-th"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-08-30T18:04:17Z","title_canon_sha256":"b870bfb11b9d92c36e2bfacb46a731ee8057353571664f1d7d1bfca4a60d2e70"},"schema_version":"1.0","source":{"id":"1808.10469","kind":"arxiv","version":2}},"canonical_sha256":"77c84ea6aa3d280c97ad470e2212d2b3543b0e203984d3e8774a6547d1329f25","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"77c84ea6aa3d280c97ad470e2212d2b3543b0e203984d3e8774a6547d1329f25","first_computed_at":"2026-05-18T00:04:20.061007Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:04:20.061007Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"1pbTr4u+buNmosW2flWr9SbHSECcFxtAbuRIHMaUVcBHwmFMxaXH0I3yst70KgFnBYCuJk0TY7mlEvAQOx33Dg==","signature_status":"signed_v1","signed_at":"2026-05-18T00:04:20.061663Z","signed_message":"canonical_sha256_bytes"},"source_id":"1808.10469","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:915c9eed0cf8b6a802f0f5e988b7d8cc66fc74f76ed3ea57467eee53bae5d595","sha256:48dcf6accee6d82f6803a9ca36c3bdab45261a47be01d8acf7b1a2e8bba9c62d"],"state_sha256":"fe4c18eca4ece47f66f8b992a7cabef54bc7dbbde0694c8477334c66c4e2035f"}