Predicted precritical second-sound damping in superfluidHe4: "High-temperature" expansion

A "high-temperature" expansion in powers of ${\mathrm{}\left|t\right|\mathrm{}}^{-\frac{2}{3}}$, where $t$ is the reduced temperature, is employed to predict the first rise above background in the second-sound damping as the $\lambda$ point is approached from below. We show that this precritical rise is determined by the corresponding precritical rise in the thermal conductivity as the $\lambda$ point is approached from above.