{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"a5742de60fdab940284ccb9afa57044b23a9a3b330526b4d41642683c96193ae","created":"2026-10-03T07:18:00Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"acffc485d3bba5bffceb15a348798c70834581d89b11c6b884a79d42cb53d065","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"cm.light-induced-sc.k3c60-transient-state","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"After a mid-infrared pulse, the fulleride K3C60 shows an optical response like a superconductor at temperatures far above its normal $20\\ \\mathrm{K}$ transition, lasting up to nanoseconds. What state of matter this is remains unknown.","posed_since":"2016","precise":"K3C60 (equilibrium $T_{\\mathrm{c}} = 20\\,\\mathrm{K}$) excited at mid-infrared or terahertz frequencies shows a transient gap in $\\sigma_1(\\omega)$ and $\\sigma_2(\\omega) \\sim 1/\\omega$ well above $T_{\\mathrm{c}}$, with metastable states lasting nanoseconds at high fluence. Identify the state (transient superconductor, fluctuating pairs, high-mobility normal state, or analysis artifact) and its microscopic mechanism. Answer: a mechanism consistent with optical, transport and magnetic data.","problem_ref":null,"references":"","settled_by":"Transient magnetic, zero-resistance and optical measurements on the same samples, explained by one microscopic model.","status_note":"Dodge, Lopez and Sahota (arXiv:2307.00204, 2023) argue the optical evidence comes from an analysis flaw and reflects photoenhanced carrier mobility; a 2025 field-expulsion search (De Vecchi et al., arXiv:2502.20276) set only an upper limit.","title":"What is the photoexcited state of K3C60 above $T_{\\mathrm{c}}$","topic_ref":"a4f7f1ae5dbd43b5f6c513a7a2b6e1f0d22cc39b03da4e8f25e23fa5acb4d309"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"1ded679c5ad8b8ea375c402469b19aa10eda14eeafcea7513745efd2fc8cc18d","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"732975ded6526dfcfb3f81e7611b1f4878c724d755ef38d853b799e706cfb068","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"fkritewC_KagxkDyT4r4FV_C4Hhul3kOnQBR-wUTBcQbsZyAeDSeAfrdBjHu-bLjy2xb8ahhj4tfWYstujupAw"},"schema":"pubphys.envelope/1"},"record_hash":"1ded679c5ad8b8ea375c402469b19aa10eda14eeafcea7513745efd2fc8cc18d","leaf_index":1065}