On the existence of a bound state of two adsorbed He atoms

A. V. Maksimychev, L. I. Men’shikov, P. L. Men’shikov

The interaction between two slow atoms adsorbed on the surface is considered. It is shown that, similar to Efimov states of three particles, this system has a bound state at any sign of the scattering length.

Richard David Etters, J. C. Raich, Prakash Chand

Ajoy Kumar Ghatak, S. Lokanathan

Massimo Boninsegni

Quantum Monte Carlo simulations confirm the existence of a bound state of a single He-3 atom at a free superfluid He-4 surface in three dimensions, localized within a ~10-A thick low-density He-4 surface layer, with a binding energy of approximately 4 K with respect to vacuum. As the temperature is raised above ~ 1 K the He-3 atom leaves the surface to dissolve into the superfluid. The situation is entirely different in two dimensions, as the He-3 atom is excluded from the superfluid and no surface bound state exists. Results are also presented for the a He-3 atom binding to nanoscale size He-4 clusters adsorbed on weak substrates, a physical system that may allow for the observation of some of the physics predicted for extended surfaces. It is shown that a He-3 bound state localized at the perimeter of sufficiently small (a few tens of atoms) clusters exists not just on Cs, as previously reported, but on all alkali substrates.

Stefan V. Mashkevich, S. I. Vilchynskyy

Alexei S. Ioselevich