arXiv subjects

Edgar Genio

Publications and source records attributed to Edgar Genio.

2 recordsLinked to original sources

arXiv2002

Finite-Size Scaling and Universality of the Thermal Resistivity of Liquid $^4$He near $T_λ$

We present measurements of the thermal resistivity $ρ(t,P,L)$ near the superfluid transition of $^4$He at saturated vapor pressure and confined in cylindrical geometries with radii $L=0.5$ and 1.0 $μ$m ($t\equiv T/T_λ(P) - 1$). For $L = 1.0 μ$m measurements at six pressures $P$ are presented. At and above $T_λ$ the data are consistent with a universal scaling function $F=(L/ξ_0)^{x/ν}(R/R_0)$, $X= (L/ξ_0)^{1/ν}t$ valid for all $P$ ($R_0$ and $x$ are the pressure-dependent amplitude and effective exponent of the bulk resistivity $R$ and $ξ= ξ_0 t^{-ν}$ is the correlation length).

cond-mat↗

arXiv2001

Singularity in the boundary resistance between superfluid $^4$He and a solid surface

We report new measurements in four cells of the thermal boundary resistance $R$ between copper and $^4$He below but near the superfluid-transition temperature $T_λ$. For $10^{-7} \leq t \equiv 1 - T/T_λ\leq 10^{-4}$ fits of $R = R_0 t^{x_b} + B_0$ to the data yielded $x_b \simeq 0.18$, whereas a fit to theoretical values based on the renormalization-group theory yielded $x_b = 0.23$. Alternatively, a good fit of the theory to the data could be obtained if the {\it amplitude} of the prediction was reduced by a factor close to two. The results raise the question whether the boundary conditions used in the theory should be modified.

cond-mat↗