Random-matrix ensembles in p-wave vortices

Abstract

In disordered vortices in p-wave superconductors the two new random-matrix ensembles may be realized: B and DIII-odd (of so(2N+1) and so(4N+2)/u(2N+1) matrices respectively). We predict these ensembles from an explicit analysis of the symmetries of Bogoliubov-deGennes equations in three examples of vortices with different p-wave order parameters. A characteristic feature of the novel symmetry classes is a quasiparticle level at zero energy. Class B is realized when the time-reversal symmetry is broken, and class DIII-odd when the time-reversal symmetry is preserved. We also suggest that the main contribution to disordering the vortex spectrum comes from the distortion of the order parameter around impurities.