{"paper":{"title":"Linear perturbations in a universe with a cosmological constant","license":"","headline":"","cross_cats":["gr-qc"],"primary_cat":"astro-ph","authors_text":"Antonio Vale, Jose' P. S. Lemos","submitted_at":"2001-01-28T17:52:55Z","abstract_excerpt":"There are now evidences that the cosmological constant $\\Lambda$ has a non-zero positive value. Alternative scenarios to a pure cosmological constant model are provided by quintessence, an effective negative pressure fluid permeating the universe. Recent results indicate that the energy density $\\rho$ and the pressure $p$ of this fluid are constrained by $-\\rho\\leq p \\buildrel<\\over\\sim-0.6 \\rho$. Since $p=-\\rho$ is equivalent to the pure cosmological constant model, it is appropriate to analyze this particular, but important, case further. We study the linear theory of perturbations in a Frie"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0101500","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/astro-ph/0101500/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"}