{"paper":{"title":"Cosmological implications of ultra-light axion-like fields","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ph"],"primary_cat":"astro-ph.CO","authors_text":"Daniel Grin, Marc Kamionkowski, Tanvi Karwal, Tristan L. Smith, Vivian Poulin","submitted_at":"2018-06-27T18:00:01Z","abstract_excerpt":"Cosmological observations are used to test for imprints of an ultra-light axion-like field (ULA), with a range of potentials $V(\\phi)\\propto[1-\\cos(\\phi/f)]^n$ set by the axion-field value $\\phi$ and decay constant $f$. Scalar field dynamics dictate that the field is initially frozen and then begins to oscillate around its minimum when the Hubble parameter drops below some critical value. For $n\\!=\\!1$, once dynamical, the axion energy density dilutes as matter; for $n\\!=\\!2$ it dilutes as radiation and for $n\\!=\\!3$ it dilutes faster than radiation. Both the homogeneous evolution of the ULA a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1806.10608","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":""},"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"}