{"paper":{"title":"Defocusing dark energy: Raychaudhuri diagnostics beyond $w<-1/3$ and the phantom divide","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"gr-qc","authors_text":"Antonio De Felice, N. Merve Uzun, \\\"Ozg\\\"ur Akarsu","submitted_at":"2026-07-20T14:41:08Z","abstract_excerpt":"In general relativity, cosmic acceleration is timelike defocusing of the comoving congruence and requires a negative total active gravitational mass density, $\\mathcal{M}_{\\rm tot}=\\rho_{\\rm tot}+3p_{\\rm tot}<0$. The criterion $w\\equiv p/\\rho<-1/3$ diagnoses sector repulsion only for $\\rho>0$: the inequality reverses for $\\rho<0$, and ratio variables are ill-defined at $\\rho=0$ even when the stress-energy tensor is finite. For sign-changing effective dark energy (DE), as in $\\Lambda_{\\rm s}$CDM-type histories, we instead use the signed density $\\rho_{\\rm de}$ and two branch-independent combina"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2607.18008","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/2607.18008/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"}