{"paper":{"title":"Fluid Interpretation of Cardassian Expansion","license":"","headline":"","cross_cats":["astro-ph"],"primary_cat":"hep-ph","authors_text":"Katherine Freese (UMich), Paolo Gondolo (CWRU)","submitted_at":"2002-09-26T19:48:33Z","abstract_excerpt":"A fluid interpretation of Cardassian expansion is developed. Here, the Friedmann equation takes the form $H^2 = g(\\rho_M)$ where $\\rho_M$ contains only matter and radiation (no vacuum). The function $g(\\rhom)$ returns to the usual $8\\pi\\rhom/(3 m_{pl}^2)$ during the early history of the universe, but takes a different form that drives an accelerated expansion after a redshift $z \\sim 1$. One possible interpretation of this function (and of the right hand side of Einstein's equations) is that it describes a fluid with total energy density $\\rho_{tot} = {3 m_{pl}^2 \\over 8 \\pi} g(\\rhom) = \\rhom "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ph/0209322","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/hep-ph/0209322/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"}