{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"068bd359772a8f91f45ff77eec4c0655b384181300dfae25e9a32be9ed2d50b1","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b","f98c6077c7bf30ee96d8d474f278781ee9ab4b0f3185abeadd4a8a958d175fd5"],"salt":"fa65fadbb0b42fb6286a4a1a836ab4f2a0adbeddd6d5c64f9503776f68d24ea8","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":["ai:gpt-5.5"],"external_id":"cm.cuprate-pseudogap.tstar-transition","kind":"well-posed","literature_status":"contested","n":"2","parents":[],"plain":"If the pseudogap is a true phase, crossing its boundary should leave a mark in heat capacity, as freezing does for water; no such mark has been clearly seen.","posed_since":"","precise":"In a clean hole-doped cuprate (YBa2Cu3O6+x or HgBa2CuO4+d), determine whether the free energy is nonanalytic along $T*(p)$: resolve a specific-heat or thermal-expansion anomaly at $T*$ matching the symmetry breaking claimed by polarized neutron scattering, torque magnetometry and polar Kerr rotation, or bound $\\Delta C/T$ below the value required by a mean-field transition with the claimed order parameter. An answer is a detected singularity with its exponent, or such a bound.","problem_ref":"f98c6077c7bf30ee96d8d474f278781ee9ab4b0f3185abeadd4a8a958d175fd5","references":"","settled_by":"High-resolution calorimetry or thermal expansion through $T*$ on crystals in which torque or neutron onsets are measured on the same piece.","status_note":"Resonant ultrasound (2013) found an elastic anomaly along $T*(p)$, and torque magnetometry (2017) and polarized neutron data indicate symmetry breaking near $T*$, but no calorimetric anomaly at $T*$ has been resolved and the neutron results are disputed.","title":"Is the pseudogap temperature $T*$ a thermodynamic phase transition?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"e373c58c0545fb1861bfc66434e82c259fc16f29ce5eda0212eaeace260fee82","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"9ceb6afd3e62eee9e6e5ce8458fc2a4183ca9adb850d90b55b966912ff02cb14","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"jJihfj9iydHA2KLFpqKO-uZmX2GoOy-XS0zGeZ1PQXaOujsLtpWYy_NzscrLsB7Lm4URSMuSp1QTdcCeJiHaBw"},"schema":"pubphys.envelope/1"},"record_hash":"e373c58c0545fb1861bfc66434e82c259fc16f29ce5eda0212eaeace260fee82","leaf_index":2728}