Van der Waals effects at the superfluid transition of confined ⁴Helium

We explore the role which the van der Waals field plays in the behavior of the superfluid density of confined helium near Tλ. This effect can be calculated in the context of ψ-theory. The influence of a solid wall is incorporated into the equation for the order parameter via a spatially-dependent transition temperature. The equation is solved numerically. We first calculate the scaling function without wall interactions for the case of 2D, 1D, and 0D dimensionality crossover. We find that upon introducing the van der Waals field, its influence is too small, and in the wrong direction to explain experimental observations.