{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"902d12b8760e771597cd1bce0045aef6297615f112f89f70d622a0a7fdd95a36","created":"2026-10-03T07:18:09Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"c671351229e3dfee212e51b1b7ab8957aff9ddde3c583b60d9cc26c749182e3a","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"qft.resurgence.renormalon-semiclassics","kind":"phenomenon","literature_status":"contested","n":"1","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 (4D Yang-Mills and QCD, 2D $O(N)$, $CP^{N-1}$ 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":null,"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":"88aaaf6de44f69e9ea9e8b5c7e7832ec7f2fa0d6edca48ad49c04f5b96cbb185"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"550395cea74fb01dfce230e366c9f67c7f9cbc13c2b86a9676013f21bccc2bc2","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"453f1ed3b52eacd994ba2bffc531b4d11fa1187e54e7fa2d159f0b1d7e5cf3ec","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"0JaJG-NtGMjy-dgjb5XfVq2P6Py1tw_dpT43C4GtMdfYDbY2mNkcfsd-dd5Th9tW5DYHlqqpx2FU0gacfXB3DQ"},"schema":"pubphys.envelope/1"},"record_hash":"550395cea74fb01dfce230e366c9f67c7f9cbc13c2b86a9676013f21bccc2bc2","leaf_index":1939}