Far-Infrared Absorption and Tunneling Conductance of Anisotropic Singlet Superconductors at Finite Temperatures

Abstract
The far-infrared absorption spectra and the quasi-particle tunneling conductance are calculated at finite temperatures in poly-crystalline samples of superconductors with anisotropic singlet pairing. Currently observed small 2Δ/k B T c ratio in far-infrared measurements and the large ratio in tunneling measurements for high-T c oxides are shown to be consistent with the anisotropic pairing.