{"paper":{"title":"Microscopic theory of the lower critical field in superconducting thin-film strips","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.supr-con","authors_text":"Takayuki Kubo","submitted_at":"2026-07-07T06:35:08Z","abstract_excerpt":"The lower critical field \\(B_{c1}\\) of a narrow superconducting thin-film strip sets the thermodynamic scale for vortex-free operation in a perpendicular magnetic field. The standard Pearl--London estimate requires a phenomenological vortex-core cutoff, because the London theory does not resolve the core. We formulate a microscopic theory for a dirty strip by solving the two-dimensional Usadel equations in the film plane, with the applied field included directly in the gauge-invariant momentum. Self-consistent vortex and Meissner solutions are computed at fixed field, and \\(B_{c1}\\) is obtaine"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2607.05890","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2607.05890/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}