{"paper":{"title":"Constraining Quintessential Inflation with ACT: A Gauss-Bonnet Gateway","license":"http://creativecommons.org/publicdomain/zero/1.0/","headline":"Non-minimal Gauss-Bonnet couplings shift quintessential inflation predictions to match ACT's higher scalar spectral index.","cross_cats":["gr-qc"],"primary_cat":"astro-ph.CO","authors_text":"Imtiyaz Ahmad Bhat, Mayukh R. Gangopadhyay, M. Sami, Yogesh","submitted_at":"2026-04-16T06:10:52Z","abstract_excerpt":"Recent results from the Atacama Cosmology Telescope (ACT), indicating a higher and more tightly constrained scalar spectral index, $n_s = 0.9743 \\pm 0.0034$, place several inflationary models under tension, with quintessential inflation pushed close to or beyond the $2\\sigma$ boundary in the $r$--$n_s$ plane. In this work, we revisit quintessential inflation within the framework of Einstein--Gauss--Bonnet (EGB) gravity, where a scalar field non-minimally coupled to the Gauss--Bonnet invariant modifies the inflationary dynamics.\n  We consider three representative coupling functions -- exponenti"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"the exponential and sech-type couplings can shift the predicted values of r and ns into the 1σ region allowed by ACT, thereby restoring consistency with observations","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The three chosen functional forms for the scalar-Gauss-Bonnet coupling are representative, and the model-independent reheating parametrization remains valid even without a potential minimum.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Einstein-Gauss-Bonnet corrections with exponential or sech couplings shift quintessential inflation into the 1 sigma ACT region for r and ns, while tanh coupling remains disfavored.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Non-minimal Gauss-Bonnet couplings shift quintessential inflation predictions to match ACT's higher scalar spectral index.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"86ed611ae419475054c3d96b1ef33985cd977e08841830c9e02639a37e61c244"},"source":{"id":"2604.14659","kind":"arxiv","version":2},"verdict":{"id":"4da58249-b531-4a25-a384-37a5b5e33fe9","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-10T10:26:27.407658Z","strongest_claim":"the exponential and sech-type couplings can shift the predicted values of r and ns into the 1σ region allowed by ACT, thereby restoring consistency with observations","one_line_summary":"Einstein-Gauss-Bonnet corrections with exponential or sech couplings shift quintessential inflation into the 1 sigma ACT region for r and ns, while tanh coupling remains disfavored.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The three chosen functional forms for the scalar-Gauss-Bonnet coupling are representative, and the model-independent reheating parametrization remains valid even without a potential minimum.","pith_extraction_headline":"Non-minimal Gauss-Bonnet couplings shift quintessential inflation predictions to match ACT's higher scalar spectral index."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.14659/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"}