{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"5ee672dcad657c5d49c4911eb0719c9ed068783c6b64037354f2e9845cef5a19","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["62a701b99f658e98e4fb13cdc63ce8564ca3644b7ee696819ee52c213bae791b","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"06fe201850befa59df65b15cffa3c9d6d8bf035a47b463f87b544a19043630aa","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"cm.light-induced-sc.k3c60-diamagnetism","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Superconductors push out magnetic fields (the Meissner effect). A measurement on light-driven $\\mathrm{K_3C_{60}}$ has so far only set a limit on this effect.","posed_since":"","precise":"Measure the transient volume susceptibility $\\chi_v$ of $\\mathrm{K_3C_{60}}$ at $T > 20\\ \\mathrm{K}$ after mid-infrared excitation; complete expulsion is $\\chi_v = -1/(4\\pi)$ in CGS, reduced by the excited volume fraction. Answer yes or no: is $\\chi_v(t, T)$ distinguishable from zero within its uncertainty and consistent with superconducting diamagnetism of the excited volume?","problem_ref":"62a701b99f658e98e4fb13cdc63ce8564ca3644b7ee696819ee52c213bae791b","references":"","settled_by":"Time-resolved magneto-optic or nitrogen-vacancy magnetometry on single crystals or dense films with better field resolution than the 2025 powder measurement.","status_note":"A 2025 Faraday-rotation search on powders (De Vecchi et al., arXiv:2502.20276) bounded the response to less than about 10 percent of complete expulsion, which does not decide the question.","title":"Does photoexcited $\\mathrm{K_3C_{60}}$ above $T_{c}$ expel magnetic field?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"e9c0c9df46671b2d5d9ff29bc083d1eff640e4c02dd62147521b87470eb0fa78","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"6a75e920e98dd84cb938da97b7d22c614449aa5df39e8bbb70a4bc06da4c2641","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"0q2DZA5XXb75uB68Lh-s409X5wV9oO9d3PIQI_po0Koku78tRcK0TIvwQKR3EwIA3JPFYTqX0Mee04KliknUBA"},"schema":"pubphys.envelope/1"},"record_hash":"e9c0c9df46671b2d5d9ff29bc083d1eff640e4c02dd62147521b87470eb0fa78","leaf_index":2906}