{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"40378c849bcdf9a6258599be8894578fd9e7f7dfddb237bdc59d95efff7ff3f4","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["946651e45560029973e85184727aeb29e0c77ad6e6c7e6779b82d81a1358b32c","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"c74cedd524f4fed2a2b2ff33a5bf476e0741a05371d945e4de62e7eaf3785792","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"cm.cuprate-pseudogap.origin","kind":"phenomenon","literature_status":"contested","n":"2","parents":[],"plain":"Above the superconducting temperature, underdoped cuprates lose many low-energy electron states, a partial gap called the pseudogap; it is unclear whether this is a separate phase of matter, pairs without long-range order, or a gradual crossover.","posed_since":"1989","precise":"Identify the state below $T*(p)$ in hole-doped cuprates for $p < p* \\sim 0.19$: a broken-symmetry phase (intra-unit-cell loop currents, nematic order, pair density wave, fluctuating antiferromagnet), a fractionalized metal with small Fermi pockets ($\\mathrm{FL}*$), or a crossover. An answer specifies the order parameter or topological character and accounts for the Fermi arcs, the Knight-shift suppression, and the drop of Hall carrier density from $1+p$ to p near $p*$.","problem_ref":"946651e45560029973e85184727aeb29e0c77ad6e6c7e6779b82d81a1358b32c","references":"","settled_by":"A symmetry-resolved or thermodynamic measurement establishing a phase transition at $T*$, plus a theory that reproduces the carrier-density change at $p*$ and the arc spectrum.","status_note":"","title":"What is the pseudogap state of underdoped cuprates?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"e138d0eb462670952c68d898201fec5bb8e29b32fe2fbe2c488180f7378404c2","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"5467475dd3a00a8c5ccc2e8d16c4001b8e8dbc93c28e3be7c1717b3a18920b7a","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"emDVPdfr6fwW6RpWEJIVdp_lDm-1cERb7sbLui8NXloyXdiMO1oHGxjTS8AAeVPSef2SbkoP4Hq0zV2e307aBg"},"schema":"pubphys.envelope/1"},"record_hash":"e138d0eb462670952c68d898201fec5bb8e29b32fe2fbe2c488180f7378404c2","leaf_index":2722}