Frequency-dependent Inter-pseudospin Solutions of Superconducting Strontium Ruthenate

Recent experimental improvements have shifted the discussion on superconducting Sr₂RuO₄ away from the chiral p-wave solution, yet experiments give seemingly different pictures that are challenging to reconcile. In this multi-orbital system with important spin-orbit coupling, pairing mediated by electronic correlations leads to superconducting order parameters with rich structures. Taking advantage of pseudospin and inversion symmetries, we investigate the possible superconducting instabilities mediated by these spin and charge fluctuations. We find that spin-orbit coupling ubiquitously mixes even and odd contributions in orbital, spin and frequency spaces. We find two different leading inter-pseudospin symmetries: a B_1g⁺ and an A_2g^- that have intra-orbital components respectively even and odd in Matsubara frequencies. An accidental degeneracy between those could help unify experimental evidence.