{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2023:H6QY3T64DYCNLTFEGG4FN3O425","short_pith_number":"pith:H6QY3T64","schema_version":"1.0","canonical_sha256":"3fa18dcfdc1e04d5cca431b856eddcd76858435a8698e193f19623abbad0acc9","source":{"kind":"arxiv","id":"2310.16500","version":2},"attestation_state":"computed","paper":{"title":"Simultaneously probing the sound speed and equation of state of the early Universe with pulsar timing arrays","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["gr-qc"],"primary_cat":"astro-ph.CO","authors_text":"Lang Liu, You Wu, Zu-Cheng Chen","submitted_at":"2023-10-25T09:43:47Z","abstract_excerpt":"Recently, several major pulsar timing array (PTA) collaborations have assembled strong evidence for the existence of a gravitational-wave background at frequencies around the nanohertz regime. Assuming that the PTA signal is attributed to scalar-induced gravitational waves, we jointly employ the PTA data from the NANOGrav 15-year data set, PPTA DR3, and EPTA DR2 to probe the conditions of the early Universe. Specifically, we explore the equation of state parameter ($w$), the reheating temperature ($T_\\mathrm{rh}$), and the sound speed ($c_s$), finding $w = 0.59^{+0.36}_{-0.40}$ (median + $90\\%"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"2310.16500","kind":"arxiv","version":2},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.CO","submitted_at":"2023-10-25T09:43:47Z","cross_cats_sorted":["gr-qc"],"title_canon_sha256":"e820a845283a35995636e6f0955850ad4b43a63b0e79e5744a60c964db1147e3","abstract_canon_sha256":"e9df125d9082aafa0ba17f4e1212383f3cfab4bac2ff3f76fd49211914f6fa96"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T10:39:15.789429Z","signature_b64":"3CzCoRKFSDInN/zi+vrSqoAn/WqkYHLxcnsSjNbT5pLCpAj2c0snusd78/Ld5Y6FGTRsAiaLL7p31p9UIcB1DA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"3fa18dcfdc1e04d5cca431b856eddcd76858435a8698e193f19623abbad0acc9","last_reissued_at":"2026-07-05T10:39:15.788900Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T10:39:15.788900Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Simultaneously probing the sound speed and equation of state of the early Universe with pulsar timing arrays","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["gr-qc"],"primary_cat":"astro-ph.CO","authors_text":"Lang Liu, You Wu, Zu-Cheng Chen","submitted_at":"2023-10-25T09:43:47Z","abstract_excerpt":"Recently, several major pulsar timing array (PTA) collaborations have assembled strong evidence for the existence of a gravitational-wave background at frequencies around the nanohertz regime. Assuming that the PTA signal is attributed to scalar-induced gravitational waves, we jointly employ the PTA data from the NANOGrav 15-year data set, PPTA DR3, and EPTA DR2 to probe the conditions of the early Universe. Specifically, we explore the equation of state parameter ($w$), the reheating temperature ($T_\\mathrm{rh}$), and the sound speed ($c_s$), finding $w = 0.59^{+0.36}_{-0.40}$ (median + $90\\%"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2310.16500","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2310.16500/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"},"aliases":[{"alias_kind":"arxiv","alias_value":"2310.16500","created_at":"2026-07-05T10:39:15.788961+00:00"},{"alias_kind":"arxiv_version","alias_value":"2310.16500v2","created_at":"2026-07-05T10:39:15.788961+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2310.16500","created_at":"2026-07-05T10:39:15.788961+00:00"},{"alias_kind":"pith_short_12","alias_value":"H6QY3T64DYCN","created_at":"2026-07-05T10:39:15.788961+00:00"},{"alias_kind":"pith_short_16","alias_value":"H6QY3T64DYCNLTFE","created_at":"2026-07-05T10:39:15.788961+00:00"},{"alias_kind":"pith_short_8","alias_value":"H6QY3T64","created_at":"2026-07-05T10:39:15.788961+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":4,"internal_anchor_count":0,"sample":[{"citing_arxiv_id":"2505.16820","citing_title":"Isotropy, anisotropies and non-Gaussianity in the scalar-induced gravitational-wave background: diagrammatic approach for primordial non-Gaussianity up to arbitrary order","ref_index":289,"is_internal_anchor":false},{"citing_arxiv_id":"2512.08301","citing_title":"Isocurvature Induced Gravitational Waves at Pulsar Timing Arrays","ref_index":87,"is_internal_anchor":false},{"citing_arxiv_id":"2604.26513","citing_title":"Transient Parity Violation during Inflation: Implications for PTA Gravitational Waves","ref_index":26,"is_internal_anchor":false},{"citing_arxiv_id":"2604.20063","citing_title":"Purely quadratic non-Gaussianity from tachyonic instability: Primordial black holes and scalar-induced gravitational waves","ref_index":42,"is_internal_anchor":false}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425","json":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425.json","graph_json":"https://pith.science/api/pith-number/H6QY3T64DYCNLTFEGG4FN3O425/graph.json","events_json":"https://pith.science/api/pith-number/H6QY3T64DYCNLTFEGG4FN3O425/events.json","paper":"https://pith.science/paper/H6QY3T64"},"agent_actions":{"view_html":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425","download_json":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425.json","view_paper":"https://pith.science/paper/H6QY3T64","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2310.16500&json=true","fetch_graph":"https://pith.science/api/pith-number/H6QY3T64DYCNLTFEGG4FN3O425/graph.json","fetch_events":"https://pith.science/api/pith-number/H6QY3T64DYCNLTFEGG4FN3O425/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425/action/timestamp_anchor","attest_storage":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425/action/storage_attestation","attest_author":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425/action/author_attestation","sign_citation":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425/action/citation_signature","submit_replication":"https://pith.science/pith/H6QY3T64DYCNLTFEGG4FN3O425/action/replication_record"}},"created_at":"2026-07-05T10:39:15.788961+00:00","updated_at":"2026-07-05T10:39:15.788961+00:00"}