{"paper":{"title":"Abundant production of scalars and axions from phase transition bubble expansion","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"hep-ph","authors_text":"Andrea Paolini, Gaurang Ramakant Kane, Isabel Garcia Garcia, John March-Russell","submitted_at":"2026-08-03T18:00:02Z","abstract_excerpt":"We revisit aspects of particle production during cosmological first-order phase transitions, and show that the expansion of true-vacuum bubbles can be a copious source of particle production. Specifically, for a massive spin-0 field linearly coupled to the bubble profile, spherical bubbles expanding even at \\emph{constant} radial velocity efficiently produce particles until the local-rest-frame radius of curvature of the bubble wall exceeds the particle Compton wavelength -- contrary to the expectation that walls moving at constant speed cannot radiate. We compute the momentum spectrum of the "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2608.02729","kind":"arxiv","version":1},"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/2608.02729/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"}