{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"67044148ac68c08fbfec908ced23c53b9b7f46ce94ff6dd89a7d2a4073822059","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"8efddfa9eeed3a11d2457c8f069d1e2889febc7d26afbd8e1a476feb6a97ffd0","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"amo.efimov-universality.four-body-parameter","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"Four atoms can also bind into states attached to each Efimov molecule. The question is whether their positions follow from the three-atom number alone, or need extra information.","posed_since":"2009","precise":"Zero-range theory predicts tetramer loss resonances at a_4,1 ~ 0.43 a_- and a_4,2 ~ 0.90 a_- (von Stecher, D'Incao, Greene 2009). With realistic van der Waals interactions, determine whether these ratios are universal to 5% or depend on short-range four-body physics. Answer: yes or no with a computed and measured spread across species.","problem_ref":null,"references":"","settled_by":"Precision four-body loss spectroscopy in several species with a matching van der Waals four-body calculation.","status_note":"Cesium experiments since 2009 roughly match the zero-range ratios, but precision tests across species are missing.","title":"Is a separate four-body parameter needed for Efimov-linked tetramers?","topic_ref":"339b6d63b4f6e3414be07628eacf49cfd6937fceb21d43c10a8b4202c093ede0"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f78f3f5e34fe452eeba889276837aeb8e5ea9d65146057511cb4bc61ff8d06b0","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"6909945b50f214a292806738057d2bea89b22bfc092f92c768f9f18f4bd28828","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"5QF7homYL6csD96CNW3tvO0RBP-wzT6zH_BLIncmW27wpBEcIfGqpC6caxPBAtD3h7piCCX5AfwdKc8VSFSKDA"},"schema":"pubphys.envelope/1"},"record_hash":"f78f3f5e34fe452eeba889276837aeb8e5ea9d65146057511cb4bc61ff8d06b0","leaf_index":401}