Nodal or fully gapped superconducting order in magic-angle graphene

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 $T \to 0$).

A phase-sensitive Josephson or quasiparticle-interference measurement identifying gap sign changes, consistent with low-temperature $\kappa/T$.