VARIATIONAL MONTE-CARLO STUDIES OF THE RATE OF TRANSMISSION OF AN ATOMIC HELIUM BEAM THROUGH A SLAB OF SUPERFLUID-HELIUM BY A CONDENSATE MEDIATED PROCESS

We report variational Monte Carlo calculations which give amplitudes a nd phases of the reflected and transmitted components of states repres enting scattering of helium atoms normally incident on a superfluid He -4 slab. The wave function describes a previously postulated condensat e mediated process [J. W. Halley et al., Phys. Rev. Lett. 71, 2429 (19 93)] and the results are consistent with uncertainty principle argumen ts suggesting that the transmission time for thin (but macroscopic) sa mples will be independent of slab thickness.