{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"a7dab7c0b89c7890f417aeed5031078b8d8454bb450cd8d80b61fcd5f977bc77","created":"2026-10-03T07:18:00Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["4e26afc00b7011defe0fb8dd7e4edec02af962c3bb628d77fb25bedb149ad4e3","5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"5b7293274ddd4933777c90c06a4c877b1a76264329425ccd446b19ecb923b68a","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"cm.moire-graphene-superconductivity.gap-symmetry","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"4e26afc00b7011defe0fb8dd7e4edec02af962c3bb628d77fb25bedb149ad4e3","relation":"special_case"}],"plain":"The energy needed to break an electron pair may vanish along certain directions (nodes) or stay finite everywhere, and which case holds narrows the possible pairing mechanisms.","posed_since":"","precise":"Determine whether the superconducting gap of magic-angle twisted bilayer graphene near $\\nu = -2 - \\delta$ has nodes on the Fermi surface, and its irreducible representation under the $D_6$ point group ($D_3$ or lower with strain) combined with valley symmetry. Existing evidence is V-shaped tunnelling spectra and power-law superfluid stiffness $D_s(T)$ for $T << T_c$. An answer requires a phase-sensitive or momentum-resolved probe (Josephson interference, quasiparticle interference, or thermal conductivity $\\kappa/T$ as $T \\to 0$).","problem_ref":null,"references":"","settled_by":"A phase-sensitive Josephson or quasiparticle-interference measurement identifying gap sign changes, consistent with low-temperature $\\kappa/T$.","status_note":"2021 tunnelling spectra and 2025 microwave superfluid-stiffness measurements (Tanaka et al., Nature 2025) both suggest gap nodes; no phase-sensitive test as of 2026.","title":"Nodal or fully gapped superconducting order in magic-angle graphene","topic_ref":"772455301d33c1cea6c0cbed25bb79fa87ea5b401f9a667e1c0b4056e25a3e52"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"75e9c297922dbf681e562fd31b2748976666c762ad9c6c9b44ae93725e36f4ec","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"e1e7b74b6a3bf41b361465abaf5ad21235bf5ba0c26c40b823a7cf90f4eb1369","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"3jUZD94G6RV9Ahwm_-7biErzwZ6mrwIJzUk4nbZuMIChjIPfymfNRCIhQ9U58iZ0erov1fEMtUaHOm66S4GKAw"},"schema":"pubphys.envelope/1"},"record_hash":"75e9c297922dbf681e562fd31b2748976666c762ad9c6c9b44ae93725e36f4ec","leaf_index":1096}