{"paper":{"title":"On the importance of radiation-era initial conditions for tensor perturbations","license":"http://creativecommons.org/licenses/by-nc-sa/4.0/","headline":"Physical initial conditions for radiation during reheating preserve the conservation of super-horizon tensor fluctuations.","cross_cats":["gr-qc","hep-ph"],"primary_cat":"hep-th","authors_text":"Dra\\v{z}en Glavan, Ignacy Sawicki, Juraj Klari\\'c, Philipp Klose","submitted_at":"2026-02-03T19:22:57Z","abstract_excerpt":"Conservation of super-horizon tensor fluctuations is crucial for connecting inflation to observations. Starting from first principles, recent works have found violations of this conservation if free-streaming radiation is produced during reheating. We show that the non-conservation is sensitive to the radiation initial state, and argue that the physical state should be affected by tensor perturbations that are already present during reheating. The deviation from super-horizon conservation is then negligible, recovering the standard result from kinetic theory. In contrast, a globally homogeneou"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The deviation from super-horizon conservation is then negligible, recovering the standard result from kinetic theory. In contrast, a globally homogeneous and isotropic plasma state leads to a large suppression of tensor amplitudes.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The physical radiation initial state during reheating is affected by tensor perturbations already present, leading to local rather than global equilibrium.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Tensor perturbations remain conserved on super-horizon scales when radiation initial conditions during reheating are locally perturbed by existing modes, unlike global equilibrium assumptions that suppress amplitudes.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Physical initial conditions for radiation during reheating preserve the conservation of super-horizon tensor fluctuations.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"68e2fb6fbe13a4bb72b3db841aef7b4a1cc390bddab2b475701bf9f2e255e1cb"},"source":{"id":"2602.03961","kind":"arxiv","version":2},"verdict":{"id":"43f6775f-021a-4f28-9d23-62335d2f4a2c","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T07:34:59.215647Z","strongest_claim":"The deviation from super-horizon conservation is then negligible, recovering the standard result from kinetic theory. In contrast, a globally homogeneous and isotropic plasma state leads to a large suppression of tensor amplitudes.","one_line_summary":"Tensor perturbations remain conserved on super-horizon scales when radiation initial conditions during reheating are locally perturbed by existing modes, unlike global equilibrium assumptions that suppress amplitudes.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The physical radiation initial state during reheating is affected by tensor perturbations already present, leading to local rather than global equilibrium.","pith_extraction_headline":"Physical initial conditions for radiation during reheating preserve the conservation of super-horizon tensor fluctuations."},"references":{"count":34,"sample":[{"doi":"","year":1981,"title":"Quantum Fluctuations and a Nonsingular Universe,","work_id":"e49bd72d-411c-4ba7-88d7-3dca20add998","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1979,"title":"Spectrum of relict gravitational radiation and the early state of the universe,","work_id":"07fa5c7f-2b63-454b-b300-d687685ea11f","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":1968,"title":"Particle creation in expanding universes,","work_id":"b4890ee8-698a-46ad-a319-a0376ee4b1af","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2018,"title":"Planck 2018 results. X. Constraints on inflation","work_id":"ac5d2133-b998-4b22-878d-b78fb5623e08","ref_index":4,"cited_arxiv_id":"1807.06211","is_internal_anchor":true},{"doi":"","year":2018,"title":"BICEP Array: a multi-frequency degree-scale CMB polarimeter","work_id":"bd41fa61-21f7-49d2-b75a-9e4be1d62990","ref_index":5,"cited_arxiv_id":"1808.00568","is_internal_anchor":true}],"resolved_work":34,"snapshot_sha256":"b0541486d11cc1ee3bec17ef6c87599c2bb76e1646cec85d98c0e314670d190b","internal_anchors":10},"formal_canon":{"evidence_count":2,"snapshot_sha256":"54fd6b45ddd39848b76fe7a50888709673614e94b42ebd6fd06250b8a0f55549"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}