{"paper":{"title":"Parametrizing growth in dark energy and modified gravity models","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["gr-qc"],"primary_cat":"astro-ph.CO","authors_text":"Antonio L. Maroto, Miguel Aparicio Resco","submitted_at":"2017-07-27T16:53:38Z","abstract_excerpt":"It is well-known that an extremely accurate parametrization of the growth function of matter density perturbations in $\\Lambda$CDM cosmology, with errors below $0.25 \\%$, is given by $f(a)=\\Omega_{m}^{\\gamma} \\,(a)$ with $\\gamma \\simeq 0.55$. In this work, we show that a simple modification of this expression also provides a good description of growth in modified gravity theories. We consider the model-independent approach to modified gravity in terms of an effective Newton constant written as $\\mu(a,k)=G_{eff}/G$ and show that $f(a)=\\beta(a)\\Omega_{m}^{\\gamma} \\,(a)$ provides fits to the nume"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1707.08964","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":""},"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"}