Superconducting kernel symmetry for an anisotropic superconductivity near and phase transitions in UPt ₃

(Received 10 April 1991, accepted 25 April 1991)

Abstract
The symmetry group of anisotropic Cooper pairing in magnetic field H includes the magnetic translations and rotations around H. On the basis of these operations Kasimir's operator which classifies the superconducting nuclei near is constructed. Such kernel classification is used to find all possible reasons of kink in -dependence existence and to interpret the phase transitions in H-T plane in the heavy-fermion superconductor UPt ₃ at the assumption of two superconducting states coexistence. The phase transition lines in space nonuniform state is shown to be either the lines of superconducting order parameter parity violation with respect to reflection in a perpendicular to magnetic field plane or the lines of triangular vortex lattice distortion or the lines of Abricosov's lattice period multiplication. Last case near signifies the phase transition with changing of magnetic vortex quantization.