Density dependence of the roton spectrum in liquidHe4

Quantum Sticking, Scattering, and Transmission ofH4eatoms from SuperfluidHCampbell1, Krotscheck2, Saarela3 1998Phys. Rev. Lett.Self Cite261120View full textAdd to dashboardCite

“…The theoretical method used here has been successfully applied to the bulk [15,16], to adsorbed films [17,18] and to droplets [19]; in the latter two it was successful in making detailed and correct predictions about surface states (ripplons and third sound) which also play a very important role in the slab geometry. The theory is adapted here to the slab geometry, including scattering states.…”

“…This is in qualitative agreement with the conclusions of Edwards and collaborators [1][2][3][4] in their results for the related helium atom scattering from the free surface of bulk helium. Our results not only provide insight into the transmission and sticking of a helium beam that was not previously available from theory or experiment, it also provides detailed predictions for the anticipated experiments on slabs.The theoretical method used here has been successfully applied to the bulk [15,16], to adsorbed films [17,18] and to droplets [19]; in the latter two it was successful in making detailed and correct predictions about surface states (ripplons and third sound) which also play a very important role in the slab geometry. The theory is adapted here to the slab geometry, including scattering states.…”

“…It is well-known from the theory of the phonon-roton spectrum of bulk liquid 4 He that these low excited states are quantitatively accounted for by a wavefunction of this type containing one-and two-body terms in F λ [15][16][17][18]:…”

REEMERGENCE OF THE COLLECTIVE MODE IN 3HE AND ELECTRON LAYERS

“…A recent study 14 demonstrates i) that additional formal approximations to simplify the numerical treatment (the "uniform limit approximation" in Ref. 13) yield quite accurate results, and, ii) that pair fluctuations are highly relevant for correctly explaining large q dynamics. The state of the art for boson dynamics is to include triplet fluctuations, 15 which correct the dynamic pair excitations in a self-consistent manner.…”

“…(13). Invoking the transformed fluctuation amplitude δv (1) , the eom for the two-pair fluctuations δu (2) read …”