{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"669d137b798b225c39004d0b29c97692419b1ebea707b4dfa88b4dc775fae6e1","created":"2026-10-03T07:18:09Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","7782085eaddc39411a355e2fffaea013881adc680060419aa177666914f1ab4e"],"salt":"f10dac8d489a10ef375758f660598c96b179b6ef3e954f24e3c58f9227de47c1","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"qft.string-nonperturbative.closed-sft","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"7782085eaddc39411a355e2fffaea013881adc680060419aa177666914f1ab4e","relation":"special_case"}],"plain":"String field theory writes string theory like an ordinary field theory and fixes many subtle quantities. Whether it defines string theory beyond the weak-coupling series is unknown.","posed_since":"","precise":"Closed superstring field theory gives a consistent perturbative definition, including D-instanton contributions with fixed normalizations (Sen 2020-2024). Determine whether it admits classical solutions describing distant backgrounds (full background independence) and a nonperturbative formulation beyond the $g_{s}$ expansion.","problem_ref":null,"references":"","settled_by":"Construction of a classical solution of closed string field theory describing a background at finite distance in moduli space, or a nonperturbative definition of its path integral.","status_note":"Background independence is shown only for nearby backgrounds (Sen and Zwiebach, 1993-1994); D-instanton normalizations computed since 2020 match dual predictions.","title":"Nonperturbative content of closed superstring field theory","topic_ref":"77b6787c01ad201a13194ef87168eea66a0756da2a9a351dc5d7a1594827efd5"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"733b5138a9331b52987f6e84e4a9772174e489552dd4417880394acd41817d75","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"7037d105b9a9e07f539cea9aacdaa456096b7fdb943980ee05e8c470949b22e4","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"4azT9dFCcFTD1-lOkE_SCdTsB_AXqKVt_J4-I6pV2_93ldE6cYvy2ctX9tuVW9m9QabeOUjX1fHjw5qqQ0GABA"},"schema":"pubphys.envelope/1"},"record_hash":"733b5138a9331b52987f6e84e4a9772174e489552dd4417880394acd41817d75","leaf_index":1954}