{"paper":{"title":"The instability of orientifolds and the end of the (string) landscape as we know it","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["gr-qc","hep-ph"],"primary_cat":"hep-th","authors_text":"Keith Copsey","submitted_at":"2013-03-19T23:25:00Z","abstract_excerpt":"Negative mass brane-like objects known as orientifolds are crucial in the construction of all presently understood realistic string compactifications and I review in general the link between negative energy objects and the existence of a landscape of metastable vacua. While in string perturbation theory these solutions are non-dynamical, and hence avoid the usual instabilities of negative tension objects, beyond perturbation theory it is well known that one may lift orientifolds in M-theory to solutions well described by classical general relativity and which consequently may be distorted in a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1303.4791","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":""},"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"}