{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"c9ccfd53d3a591f9fb1318817e8ed3e427b7b757fc4f1914498d611e800c7a23","created":"2026-10-03T07:17:59Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","946651e45560029973e85184727aeb29e0c77ad6e6c7e6779b82d81a1358b32c"],"salt":"3c991bfdd6bcf8f7a3d7cd934997ad5d56a25daa4312236e870b84168f649c89","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"cm.cuprate-pseudogap.tstar-transition","kind":"well-posed","literature_status":"contested","n":"1","parents":[{"note":"","parent_revision":"946651e45560029973e85184727aeb29e0c77ad6e6c7e6779b82d81a1358b32c","relation":"special_case"}],"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":null,"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":"0b1624cb419c381bddad004c2bf5315f0b67a5717967d1ceb30488890c34b90a"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f98c6077c7bf30ee96d8d474f278781ee9ab4b0f3185abeadd4a8a958d175fd5","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"2b80d676561146073f4b7aa5652515390f8632582319deb38b7deeca8f643756","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"CT3uhU2jHSg9bazxOuSOtIYO8B9ifjg1OjtvDcZQqM0hZq_ODcqAXALqPwJtl65DG8xynOvydyIl3u-8N73mAg"},"schema":"pubphys.envelope/1"},"record_hash":"f98c6077c7bf30ee96d8d474f278781ee9ab4b0f3185abeadd4a8a958d175fd5","leaf_index":933}