Hydrodynamical description of long wavelength density fluctuations of helium in wedges,

E. S. HERNÁNDEZ

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

APS

Año: 2010 p. 245141 - 245146

0163-1829

The hydrodynamical model that has proven successful to describe  excitations of superfluid  helium in the bulk and adsorbed on planar surfaces, cylinders and spheres, is applied to investigate the  long wavelength density fluctuation spectrum  of  $^{4}$He confined to an infinite linear wedge at zero temperature. It is found that in spite of the breaking of axial symmetry, the velocity  potentials and the shape of the meniscus can be described in terms  of an orbital quantum number or quasi--angular momentum, and that the density wave spectrum is formally similar to that of helium shells  adsorbed in a cylindrical pore. As an illustration, the stability of phonon and ripplon modes are discussed in terms of the relevant parameters of helium in a cesium wedge.