Non-Abelian Gauge Theory of Spin Triplet Superconductivity and Spin Triplet Magnon Spintronics

Abstract: We present an SU(2)xU(1) Ginzburg-Landau theory of the spin triplet ferromagnetic superconductivity which could also describe the physics of the spin triplet magnon spintronics, where the SU(2) gauge interaction of the magnon plays an important role. The theory is made of the massive photon, massless neutral magnon, massive non-Abelian magnon, and the Higgs scalar field which represents the density of the Copper pair. It has the following characteristic features, the long range magnetic interaction mediated by the massless magnon, two types of conserved supercurrents (the ordinary electromagnetic current and the spin current made of the magnons) which could explain the conversion between the charge and spin currents, and the non-Abelian Meissner effect generated by the spin current. Moreover, it has non-Abelian topological objects, the quantized non-Abelian magnonic vortex and non-Abelian magnonic monopole, as well as the ordinary Abrikosov vortex. The theory is characterized by three scales. In addition to the correlation length fixed by the mass of the Higgs field it has two different mass scales, the one fixed by the mass of the photon and the other fixed by the mass of the off-diagonal magnon. We compare the theory with the non-Abelian gauge theory of the spin doublet ferromagnetic superconductivity which could also be interpreted as an effective theory of the electron spintronics. We discuss the physical implications of the non-Abelian gauge theories in condensed matter physics.