Related papers: On The Mobile Behavior of Solid $^4$He at High Tem…
We show that, at high densities, fully variational solutions of solid-like type can be obtained from a density functional formalism originally designed for liquid 4He. Motivated by this finding, we propose an extension of the method that…
We have produced a Bose-Einstein condensate of metastable helium (4He*) containing over 1.5x10^7 atoms, which is a factor of 25 higher than previously achieved. The improved starting conditions for evaporative cooling are obtained by…
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…
Uranium is considered as a very important nuclear energy material because of the huge amount of energy released. As the main products of spontaneous decay of uranium, helium is difficult to react with uranium for its chemical inertness.…
We have studied the interaction of metastable $^4$He$_2^*$ excimer molecules with quantized vortices in superfluid $^4$He in the zero temperature limit. The vortices were generated by either rotation or ion injection. The trapping diameter…
We present deep spectroscopic (3600 - 24700 A) X-shooter observations of the bright Herbig-Haro object HH1, one of the best laboratories to study the chemical and physical modifications caused by protostellar shocks on the natal cloud. We…
Iodine (I$_2$) molecules embedded in He nanodroplets are aligned by a 160 ps long laser pulse. The highest degree of alignment, occurring at the peak of the pulse and quantified by $\langle \cos^2 \theta_{2D} \rangle$, is measured as a…
We use the thermo-mechanical effect to create a chemical potential difference between two liquid reservoirs connected to each other through Vycor rods in series with solid hcp 4He to confirm that a DC flux of atoms takes place below 600 mK,…
We present a new study of the nonlinear transport of a two-dimensional electron crystal on the surface of liquid helium confined in a 10 micrometer-wide channel in which the effective length of the crystal can be varied from 10 to 215…
This paper presents results for systems formed in a solid glassy state after nanocrystallization process above the glass temperature. We analyze electric conductivity and relaxation processes after such treatment under high temperature (HT)…
The properties of hot dense helium at megabar pressures were studied with two first-principles computer simulation techniques, path integral Monte Carlo and density functional molecular dynamics. The simulations predicted that the…
We carried out quartz crystal microbalance experiments of a 5 MHz AT-cut crystal for superfluid 4He films on Grafoil (exfoliated graphite) with a small amount of 3He up to 0.40 atoms/nm2. We found that the mass decoupling from oscillating…
A frozen, solid helium core, dubbed snowball, is typically observed around cations in liquid helium. Here we discover, using path integral simulations, that around a cationic molecular impurity, protonated methane, the $^4$He atoms are…
Germanium single crystal having 45 mm diameter and 100 mm length of 7N+ purity has been grown by Czochralski method. Structural quality of the crystal has been characterized by Laue diffraction. Electrical conduction and Hall measurements…
Metal atoms and small clusters introduced into superfluid helium (He II) concentrate there in quantized vortices to form (by further coagulation) the thin nanowires. The nanowires' thickness and structure are well predicted by a…
We explore experimentally the fluidization of vertically agitated PMMA spheres wetted by liquid $^4$He. By controlling the temperature around the $\lambda$ point we change the properties of the wetting liquid from a normal fluid (helium I)…
The deformation kinetics for glassy solid helium confined in microscopic domain at very low temperature regime was investigated using a transition-rate model considering the shear thinning behavior which means, once material being subjected…
We determine the critical temperature of a 3-d homogeneous system of hard-sphere Bosons by path-integral Monte Carlo simulations and finite-size scaling. At low densities, we find that the critical temperature is increased by the repulsive…
By use of a novel experimental design, one that provides for superfluid helium in contact with bulk hcp 4He off the melting curve, we have observed the DC transport of mass through a cell filled with solid 4He in the hcp region of the phase…
The phase diagram at zero temperature of $^4$He adsorbed on an helium incommensurate triangular solid on top of a single graphene sheet has been obtained using the diffusion Monte Carlo method. We have found that, in accordance with…