{"paper":{"title":"\\bf $\\delta M$ Formalism: A New Approach to Cosmological Perturbation Theory in Anisotropic Inflation","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"gr-qc","authors_text":"Ali Akbar Abolhasani, Alireza Talebian-Ashkezari, Nahid Ahmadi","submitted_at":"2016-09-19T13:25:39Z","abstract_excerpt":"We study the evolution of the metric perturbations in a Bianchi background in the long-wavelength limit. By applying the gradient expansion to the equations of motion we exhibit a generalized \"Separate Universe\" approach to the cosmological perturbation theory. Having found this consistent separate universe picture, we introduce the $\\delta M $ formalism for calculating the evolution of the linear tensor perturbations in anisotropic inflation models in {\\it almost} the same way that the so-called $\\delta N$ formula is applied to the super-horizon dynamics of the curvature perturbations. Simila"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1609.05893","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"}