Quaternionic superconductivity with a single-field Bogoliubov-de Gennes--Ginzburg-Landau framework and charge-4e couplings
This paper establishes a compact quaternionic field theory framework for spinful superconductivity that unifies singlet and triplet pairing into a single field, enabling the analytical derivation and numerical verification of charge-4e signatures, including vestigial order criteria, fractional flux vortices, and dominant second-harmonic Josephson effects.