{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"3608abe23e35bde7f83a5e1a5d07b23cea5a8542ea7764c17bfb6df45f8dfe38","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["550395cea74fb01dfce230e366c9f67c7f9cbc13c2b86a9676013f21bccc2bc2","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"d6e13ea19b8ed71a3ee8848adae1466344d48ee9717cee8bba44bee8ba7a3cd9","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":["ai:gpt-5.5"],"external_id":"qft.resurgence.renormalon-semiclassics","kind":"phenomenon","literature_status":"contested","n":"2","parents":[],"plain":"The factorial growth of perturbation series in QCD-like theories is linked to singularities called renormalons, which no known classical solution explains. What nonperturbative object cancels their ambiguity is unknown.","posed_since":"","precise":"In asymptotically free theories ($4\\mathrm{D}$ Yang-Mills and QCD, $2\\mathrm{D}$ $\\mathrm{O}(N)$, $\\mathrm{CP}^{N-1}$ and principal chiral models), the Borel transform of perturbation series has renormalon singularities at positions set by the one-loop beta-function coefficient, not matched by any finite-action classical solution. Identify the nonperturbative sectors (saddles, fractional instantons, bions on R^{d-1} x S^1, or OPE condensates) whose imaginary ambiguities cancel the renormalon ambiguities, and demonstrate the cancellation.","problem_ref":"550395cea74fb01dfce230e366c9f67c7f9cbc13c2b86a9676013f21bccc2bc2","references":"","settled_by":"An explicit computation in at least one asymptotically free theory showing order-by-order cancellation between the renormalon ambiguity and an identified nonperturbative sector.","status_note":"Bion proposals (2012) were questioned when their ambiguities did not match renormalon positions in compactified $\\mathrm{CP}^{N-1}$ and $\\mathrm{O}(N)$ models (2019-2024).","title":"Semiclassical origin of renormalons in asymptotically free theories","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"bb783ef8a9095ca6f8769612351d8ee8ed366522b4d765cb04fc7b4443779e41","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"c0e23fa905d2a8bcbfb1e65ce6bd2666d5538679f50c440d3180eed7c7eecc6b","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"61E8HGeMXBEk1CajVJFqzWNMsw_tLiiSWWtyDjNnDLGvnXoPm3f_ceywP_Bss-FElBVg_HhwrYuqpuaFDJ-4Bw"},"schema":"pubphys.envelope/1"},"record_hash":"bb783ef8a9095ca6f8769612351d8ee8ed366522b4d765cb04fc7b4443779e41","leaf_index":3666}