Excitations in confined helium

Abstract

We design models for helium in matrices like aerogel, Vycor or Geltech from a manifestly microscopic point of view. For that purpose, we calculate the dynamic structure function of 4He on Si substrates and between two Si walls as a function of energy, momentum transfer, and the scattering angle. The angle--averaged results are in good agreement with the neutron scattering data; the remaining differences can be attributed to the simplified model used here for the complex pore structure of the materials. A focus of the present work is the detailed identification of coexisting layer modes and bulk--like excitations, and, in the case of thick films, ripplon excitations. Involving essentially two--dimensional motion of atoms, the layer modes are sensitive to the scattering angle.

Phys. Rev. B (2003, in press)

References in corpus (1)

• Dynamics of liquid 4He in Vycor

Cited by in corpus (7)

• Thin helium film on a glass substrate
• Stability and excitations of a bilayer of strongly correlated dipolar Bosons
• Layer- and bulk roton excitations of 4He in porous media
• Surface-dominated finite size effects in nanoconfined superfluid helium
• Maxon and roton measurements in nanoconfined ${}^4$He
• Quasi-2D parahydrogen: On the verge of turning superfluid?
• On the Possibility of "Dry" Friction in Superfluid He-4