Thermal conductivity coefficient via temperature-dependent elementary excitation spectra in thin liquid ^4He(New Developments in Statistical Physics Similarities in Diversities,YITP Workshop)

Abstract

The coefficient of thermal conductivity (κ) in thin liquid ^4He is evaluated explicitly as a function of temperature via temperature-dependent two-dimensional elementary excitation spectra that are microscopic only in the long-wavelength limit. Below about 0.8K, the coefficient increases exponentially with decreasing temperature. At temperatures below about 0.3K, κ(T) in the thin film case has an T^<-5> dependence with extra temperature-dependent terms which originate from three-phonon processes.