On Calculating Spectral Intensities for Anomalous Average Values in the Theory of Superconductors with Strong Electron Correlations

摘要

In this paper, we show that allowance for properties of the Hubbard operator algebra leads to the appearance of a singular (at ω = 0) component in the total spectral intensity of the anomalous correlation function of superconductors that possess the electron pairing mechanism. In this case, the spectral theorem acquires the form of a singular integral equation. Taking these features into account, we can eliminate previously claimed forbidding of realization of the superconducting phase with the S-type symmetry of the order parameter.