{"paper":{"title":"Random phase approximation-based local natural orbital coupled cluster theory","license":"http://creativecommons.org/licenses/by/4.0/","headline":"RPA replaces MP2 as low-level theory in LNO-CC to match accuracy on gapped systems while converging faster for metals.","cross_cats":["cond-mat.mtrl-sci"],"primary_cat":"physics.chem-ph","authors_text":"Aamy Bakry, Hong-Zhou Ye, Ruiheng Song, Xiliang Gong","submitted_at":"2025-12-31T22:23:48Z","abstract_excerpt":"Practical applications of fragment embedding and closely related local correlation methods critically depend on a judicious choice of a low-level theory to define the local embedding subspace and to capture long-range electrostatic and correlation effects outside the embedding region. Second-order M{\\o}ller-Plesset perturbation theory (MP2) is by far the most widely used correlated low-level theory; however, its applicability becomes questionable in systems where MP2 is known to fail either quantitatively or qualitatively. In this work, we present the random phase approximation (RPA) as a prom"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"RPA-based LNO-CC closely matches the performance of its MP2-based counterpart for systems with sizable energy gaps, while delivering significantly faster convergence toward the canonical coupled-cluster limit for metallic systems, particularly as the thermodynamic limit is approached.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That RPA adequately captures long-range electrostatic and correlation effects outside the embedding region when used as the low-level theory in the LNO-CC framework.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"RPA-based LNO-CC matches MP2 performance for systems with energy gaps and shows faster convergence for metallic systems approaching the thermodynamic limit.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"RPA replaces MP2 as low-level theory in LNO-CC to match accuracy on gapped systems while converging faster for metals.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"c94473c0463fe4e5750a898862e677b89edd34a326bff0e8534066705ae3a540"},"source":{"id":"2601.00131","kind":"arxiv","version":2},"verdict":{"id":"a14214ee-0946-48a5-b917-3462bb182ee5","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T17:43:03.445434Z","strongest_claim":"RPA-based LNO-CC closely matches the performance of its MP2-based counterpart for systems with sizable energy gaps, while delivering significantly faster convergence toward the canonical coupled-cluster limit for metallic systems, particularly as the thermodynamic limit is approached.","one_line_summary":"RPA-based LNO-CC matches MP2 performance for systems with energy gaps and shows faster convergence for metallic systems approaching the thermodynamic limit.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That RPA adequately captures long-range electrostatic and correlation effects outside the embedding region when used as the low-level theory in the LNO-CC framework.","pith_extraction_headline":"RPA replaces MP2 as low-level theory in LNO-CC to match accuracy on gapped systems while converging faster for metals."},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":1,"snapshot_sha256":"a9eacd10ac2581e246f9a1983db44ec633cc84aba8178aa7e75e49ed811e16c1"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}