Bogoliubov angle in cuprate superconductors

Within the kinetic energy driven superconducting mechanism, the Bogoliubov angle is studied by calculation of the ratio of the low energy quasiparticle spectra at positive and negative energies. It is shown that the Bogoliubov angle increase monotonically across the Fermi crossing point, suggesting a continuous evolution of the particle and hole mixing. Our results also confirm that the basic d-wave BCS formalism under the kinetic energy driven superconducting mechanism can correctly reproduce some main low energy features of the superconducting coherence of the quasiparticle peaks in cuprate superconductors.