{"paper":{"title":"Cosmological Gravitational Waves from Ultralight Vector Dark Matter","license":"http://creativecommons.org/licenses/by/4.0/","headline":"A homogeneous ultralight vector dark matter field mixes scalar and tensor perturbations, sourcing a stochastic gravitational wave background.","cross_cats":["gr-qc"],"primary_cat":"astro-ph.CO","authors_text":"Diana L\\'opez Nacir, Tom\\'as Ferreira Chase","submitted_at":"2026-04-22T20:46:20Z","abstract_excerpt":"We compute the abundance of cosmological gravitational waves produced during the evolution of an ultralight vector (spin-1) dark matter field. A homogeneous background vector field breaks spatial isotropy, requiring a Bianchi I geometry and inducing a mixing between the scalar, vector, and tensor perturbation sectors. We derive the perturbation equations in this background and show that, as a consequence of this mixing, scalar perturbations act as a source of tensor modes, generating a stochastic GW background. The production and cosmological evolution of these gravitational waves are implemen"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"as a consequence of this mixing, scalar perturbations act as a source of tensor modes, generating a stochastic GW background","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"A homogeneous background vector field breaks spatial isotropy, requiring a Bianchi I geometry and inducing a mixing between the scalar, vector, and tensor perturbation sectors","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Ultralight vector dark matter in a Bianchi I background produces a stochastic gravitational wave spectrum through scalar-tensor perturbation mixing.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"A homogeneous ultralight vector dark matter field mixes scalar and tensor perturbations, sourcing a stochastic gravitational wave background.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"14e988cbfad620cfd25dbfd46de179caf3060dece623d5dfff6448f92672054e"},"source":{"id":"2604.21080","kind":"arxiv","version":3},"verdict":{"id":"250cc541-914c-44bc-b4ea-84894d96ec4b","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-09T22:53:04.744973Z","strongest_claim":"as a consequence of this mixing, scalar perturbations act as a source of tensor modes, generating a stochastic GW background","one_line_summary":"Ultralight vector dark matter in a Bianchi I background produces a stochastic gravitational wave spectrum through scalar-tensor perturbation mixing.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"A homogeneous background vector field breaks spatial isotropy, requiring a Bianchi I geometry and inducing a mixing between the scalar, vector, and tensor perturbation sectors","pith_extraction_headline":"A homogeneous ultralight vector dark matter field mixes scalar and tensor perturbations, sourcing a stochastic gravitational wave background."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.21080/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"ai_meta_artifact","ran_at":"2026-05-21T13:37:59.874855Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_compliance","ran_at":"2026-05-20T01:20:35.705898Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"426050a682cef839b7844b10aacb79f7739fe60578a74419d86b34dd9589742e"},"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"}