{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:EJQB3OJEUAURHAYSBOI3ZZEEO7","short_pith_number":"pith:EJQB3OJE","canonical_record":{"source":{"id":"1811.02469","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-11-06T16:21:37Z","cross_cats_sorted":["gr-qc","hep-ph"],"title_canon_sha256":"3953d1ac8b5bc661b15ca731fb9b75cedee75984e9def2387140debdfeddf91e","abstract_canon_sha256":"6792639695cb8a338133c1dcc3e2289d36ab00eb1af0b8cac3e245519d06d797"},"schema_version":"1.0"},"canonical_sha256":"22601db924a0291383120b91bce48477d8fa43fda607b8fb6bd70f391b49c2b5","source":{"kind":"arxiv","id":"1811.02469","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1811.02469","created_at":"2026-05-17T23:54:07Z"},{"alias_kind":"arxiv_version","alias_value":"1811.02469v2","created_at":"2026-05-17T23:54:07Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1811.02469","created_at":"2026-05-17T23:54:07Z"},{"alias_kind":"pith_short_12","alias_value":"EJQB3OJEUAUR","created_at":"2026-05-18T12:32:22Z"},{"alias_kind":"pith_short_16","alias_value":"EJQB3OJEUAURHAYS","created_at":"2026-05-18T12:32:22Z"},{"alias_kind":"pith_short_8","alias_value":"EJQB3OJE","created_at":"2026-05-18T12:32:22Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:EJQB3OJEUAURHAYSBOI3ZZEEO7","target":"record","payload":{"canonical_record":{"source":{"id":"1811.02469","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-11-06T16:21:37Z","cross_cats_sorted":["gr-qc","hep-ph"],"title_canon_sha256":"3953d1ac8b5bc661b15ca731fb9b75cedee75984e9def2387140debdfeddf91e","abstract_canon_sha256":"6792639695cb8a338133c1dcc3e2289d36ab00eb1af0b8cac3e245519d06d797"},"schema_version":"1.0"},"canonical_sha256":"22601db924a0291383120b91bce48477d8fa43fda607b8fb6bd70f391b49c2b5","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:54:07.006789Z","signature_b64":"4MCEBQxmTyqHH5LMnxEr+fs/EMzNaWIaKeftLc1mJSaH2K5t6V9PoeAFhMXonwj0Mg0jua0R3vfTj8gpzu3HBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"22601db924a0291383120b91bce48477d8fa43fda607b8fb6bd70f391b49c2b5","last_reissued_at":"2026-05-17T23:54:07.006340Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:54:07.006340Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1811.02469","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":"2026-05-17T23:54:07Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"JKUMSMez8yTt4kVjtOzLp5znubLa9/XSRLf1Su5LOBalvM1ij/mGPOHwWTw4TYKlht0vSc6obO9/D1yprBRUBg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-06T02:36:05.590038Z"},"content_sha256":"bde1b29ea8ba3f31c1d43f50a79a99529e40be8f9b94251dcb62cda707a5a3a7","schema_version":"1.0","event_id":"sha256:bde1b29ea8ba3f31c1d43f50a79a99529e40be8f9b94251dcb62cda707a5a3a7"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:EJQB3OJEUAURHAYSBOI3ZZEEO7","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Unraveling the effective fluid approach for $f(R)$ models in the subhorizon approximation","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["gr-qc","hep-ph"],"primary_cat":"astro-ph.CO","authors_text":"Rub\\'en Arjona, Savvas Nesseris, Wilmar Cardona","submitted_at":"2018-11-06T16:21:37Z","abstract_excerpt":"We provide explicit formulas for the effective fluid approach of $f(R)$ theories, such as the Hu & Sawicki and the designer models. Using the latter and simple modifications to the CLASS code, which we call EFCLASS, in conjunction with very accurate analytic approximations for the background evolution, we obtain competitive results in a much simpler and less error-prone approach. We also derive the initial conditions in matter domination and we find they differ from those already found in the literature for a constant $w$ model. A clear example is the designer model that behaves as $\\Lambda$CD"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1811.02469","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":"2026-05-17T23:54:07Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"rql/vq/aWS6F3xMtQprzoZEMCL6FrWd9ElOTbiko6MWuR4HDyQ9niECqq0ETUqr6UVJLGp2b7WTgGAVaVRDDDA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-06T02:36:05.590605Z"},"content_sha256":"10465f5805bb19a5a4104c5abcbf8540549d76dec3820f11ff541961abe711f5","schema_version":"1.0","event_id":"sha256:10465f5805bb19a5a4104c5abcbf8540549d76dec3820f11ff541961abe711f5"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/EJQB3OJEUAURHAYSBOI3ZZEEO7/bundle.json","state_url":"https://pith.science/pith/EJQB3OJEUAURHAYSBOI3ZZEEO7/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/EJQB3OJEUAURHAYSBOI3ZZEEO7/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":"2026-06-06T02:36:05Z","links":{"resolver":"https://pith.science/pith/EJQB3OJEUAURHAYSBOI3ZZEEO7","bundle":"https://pith.science/pith/EJQB3OJEUAURHAYSBOI3ZZEEO7/bundle.json","state":"https://pith.science/pith/EJQB3OJEUAURHAYSBOI3ZZEEO7/state.json","well_known_bundle":"https://pith.science/.well-known/pith/EJQB3OJEUAURHAYSBOI3ZZEEO7/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:EJQB3OJEUAURHAYSBOI3ZZEEO7","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":"6792639695cb8a338133c1dcc3e2289d36ab00eb1af0b8cac3e245519d06d797","cross_cats_sorted":["gr-qc","hep-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-11-06T16:21:37Z","title_canon_sha256":"3953d1ac8b5bc661b15ca731fb9b75cedee75984e9def2387140debdfeddf91e"},"schema_version":"1.0","source":{"id":"1811.02469","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1811.02469","created_at":"2026-05-17T23:54:07Z"},{"alias_kind":"arxiv_version","alias_value":"1811.02469v2","created_at":"2026-05-17T23:54:07Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1811.02469","created_at":"2026-05-17T23:54:07Z"},{"alias_kind":"pith_short_12","alias_value":"EJQB3OJEUAUR","created_at":"2026-05-18T12:32:22Z"},{"alias_kind":"pith_short_16","alias_value":"EJQB3OJEUAURHAYS","created_at":"2026-05-18T12:32:22Z"},{"alias_kind":"pith_short_8","alias_value":"EJQB3OJE","created_at":"2026-05-18T12:32:22Z"}],"graph_snapshots":[{"event_id":"sha256:10465f5805bb19a5a4104c5abcbf8540549d76dec3820f11ff541961abe711f5","target":"graph","created_at":"2026-05-17T23:54:07Z","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":"We provide explicit formulas for the effective fluid approach of $f(R)$ theories, such as the Hu & Sawicki and the designer models. Using the latter and simple modifications to the CLASS code, which we call EFCLASS, in conjunction with very accurate analytic approximations for the background evolution, we obtain competitive results in a much simpler and less error-prone approach. We also derive the initial conditions in matter domination and we find they differ from those already found in the literature for a constant $w$ model. A clear example is the designer model that behaves as $\\Lambda$CD","authors_text":"Rub\\'en Arjona, Savvas Nesseris, Wilmar Cardona","cross_cats":["gr-qc","hep-ph"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-11-06T16:21:37Z","title":"Unraveling the effective fluid approach for $f(R)$ models in the subhorizon approximation"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1811.02469","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:bde1b29ea8ba3f31c1d43f50a79a99529e40be8f9b94251dcb62cda707a5a3a7","target":"record","created_at":"2026-05-17T23:54:07Z","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":"6792639695cb8a338133c1dcc3e2289d36ab00eb1af0b8cac3e245519d06d797","cross_cats_sorted":["gr-qc","hep-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2018-11-06T16:21:37Z","title_canon_sha256":"3953d1ac8b5bc661b15ca731fb9b75cedee75984e9def2387140debdfeddf91e"},"schema_version":"1.0","source":{"id":"1811.02469","kind":"arxiv","version":2}},"canonical_sha256":"22601db924a0291383120b91bce48477d8fa43fda607b8fb6bd70f391b49c2b5","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"22601db924a0291383120b91bce48477d8fa43fda607b8fb6bd70f391b49c2b5","first_computed_at":"2026-05-17T23:54:07.006340Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:54:07.006340Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"4MCEBQxmTyqHH5LMnxEr+fs/EMzNaWIaKeftLc1mJSaH2K5t6V9PoeAFhMXonwj0Mg0jua0R3vfTj8gpzu3HBw==","signature_status":"signed_v1","signed_at":"2026-05-17T23:54:07.006789Z","signed_message":"canonical_sha256_bytes"},"source_id":"1811.02469","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:bde1b29ea8ba3f31c1d43f50a79a99529e40be8f9b94251dcb62cda707a5a3a7","sha256:10465f5805bb19a5a4104c5abcbf8540549d76dec3820f11ff541961abe711f5"],"state_sha256":"5b56d7b1c939d2859cb5107ddf8614c4c7849153473ac0c726619ac6d5a70f13"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"9WXXQcL+vKaL4lGkuS6moyOwwc0Hy5Ss2qKL4hzbGJUCR6hgX6PoDFalssKN/OurZpTLyt/W6aFnfHhQ8fwUDg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-06T02:36:05.593306Z","bundle_sha256":"a7f90f7ca315c9e72f5cc07b39ddb38392ad322e215199e5b318e6fa52727614"}}