Revision 1

Accepted · first revision · record

Title: Nodal or fully gapped superconducting order in magic-angle graphene
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.
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 $T \to 0$).
Settled by: A phase-sensitive Josephson or quasiparticle-interference measurement identifying gap sign changes, consistent with low-temperature $\kappa/T$.
Kind: well-posed
Answer type: classification
References: (empty)
Literature status: open
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.
Posed since: (empty)