Pseudo-dewetting of Superfluid Helium-4

Observation of pseudo-dewetting of helium-4 on silicon is reported. This unusual behavior mimics a finite contact angle, although the substrate is wetted. This is attributed to superfluid flow in the meniscus created by heat absorption in the substrate. The absence of any hysteresis of the pseudo contact line allows oscillation modes to propagate. Pulse propagation is shown to be in good agreement with the predicted dispersion relation.