Critical thermal boundary resistance ofHe4nearTλ

We present a unified description of the thermal boundary resistance $R_K$ (Kapitza resistance) of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ above and below $T_{\lambda }$. Using Dirichlet boundary conditions for the order parameter we determine the critical temperature dependence of $R_K$ without an adjustment of parameters. Good agreement with experimental data below $T_{\lambda }$ is found. Our local renormalization-group treatment goes beyond the conventional hydrodynamic approach and predicts the nonuniversal pressure dependencen of $R_K$ along the λ line.