THERMAL-CONDUCTIVITY AND FIRST VISCOSITY VIA TEMPERATURE-DEPENDENT ELEMENTARY EXCITATION-SPECTRA IN THIN AND BULK LIQUID-HE-4

The coefficients of thermal conductivity (kappa) and first viscosity ( eta) in thin and bulk liquid He-4 are evaluated explicitly as a functi on of temperature via the zero-temperature and temperature-dependent t wo- and three-dimensional elementary excitation spectra that are micro scopic only in the long-wavelength limit. The coefficients kappa(T) an d eta(T) obtained from the temperature-dependent spectrum have slightl y larger values than those of the zero-temperature spectrum through th e whole range of temperatures, while as the temperature approaches abs olute zero, the coefficients kappa(T) and eta(T) coincide with each ot her in both spectra. Below about 0.8 K, both coefficients increase exp onentially with decreasing temperature. At temperatures below about 0. 3 K, kappa(T) in the thin and bulk cases have T-5 and T-6 dependences, respectively, whereas eta(ph)(T) has a T-1 dependence in both dimensi ons with extra temperature-dependent terms, which originate from three -phonon processes for both excitation spectra.