Related papers: Helium at elevated pressures: Quantum liquid with …
Understand the nature of liquid structure and its evolution under different conditions is a major challenge in condensed physics and materials science. Here, we report a pressure-induced structure change spanning a wide pressure range in…
The thermo-mechanical effect in superfluid helium is used to create an initial chemical potential difference, $\Delta \mu_0$, across a solid $^4$He sample. This $\Delta \mu_0$ causes a flow of helium atoms from one reservoir filled with…
The mechanism of the roughening induced partial depinning of gliding dislocations from Helium-3 impurities is proposed as an alternative to the standard "boiling off". We give a strong argument that Helium-3 remains bound to dislocations…
We consider general theoretical models of water and in particular the nature of the motions of the hydrogen nuclei. If the motion of hydrogen nuclei is classical, then the thermodynamic pressure equation of state for heavy water wherein the…
We survey the phase diagram of high-pressure molecular hydrogen with path integral molecular dynamics using a machine-learned interatomic potential trained with Quantum Monte Carlo forces and energies. Besides the HCP and C2/c-24 phases, we…
We introduce an efficient scheme for the molecular dynamics of electronic systems by means of quantum Monte Carlo. The evaluation of the (Born-Oppenheimer) forces acting on the ionic positions is achieved by two main ingredients: i) the…
The $1s^2->1s2p(^1P)$ excitation in confined and compressed helium atoms in either the bulk material or encapsulated in a bubble is shifted to energies higher than that in the free atom. For bulk helium, the energy shifts predicted from…
We study a liquid-gas coexistence system in a container under gravity with heat flow in the direction opposite to gravity. By molecular dynamics simulation, we find that the liquid buoys up and continues to float steadily. The height at…
The recent discovery that silicon nitride membranes can be used as extremely high Q mechanical resonators makes possible a number of novel experiments, which include improved long range vacuum Casimir force measurements, and measurments of…
We investigate the possibility of ultracold neutron (UCN) storage in quantum states defined by the combined potentials of the Earth's gravity and the neutron optical repulsion by a horizontal surface of liquid helium. We analyse the…
A physical picture of normal liquid $^3$He, which accounts for both ``almost localized'' and ``almost ferromagnetic'' aspects, is proposed and confronted to experiments.
Quantum molecular dynamic (QMD) simulations are introduced to study the thermophysical properties of liquid deuterium under shock compression. The principal Hugoniot is determined from the equation of states, where contributions from…
Using quantum equations of motion for interacting bosons, stochastic molecular dynamics simulations with quantized momenta are performed for Lennard-Jones helium-4. The viscosity of the quantum liquid is significantly less than that of the…
Raising the temperature of a material enhances the thermal motion of particles. Such an increase in thermal energy commonly leads to the melting of a solid into a fluid and eventually vaporises the liquid into a gaseous phase of matter.…
We describe experiments with spin-polarized atomic hydrogen gas adsorbed on liquid $^{4}$He surface. The surface gas density is increased locally by thermal compression up to $5.5\times10^{12}$ cm$^{-2}$ at 110 mK. This corresponds to the…
In recent years, metal hydride research has become one of the driving forces of the high-pressure community, as it is believed to hold the key to superconductivity close to ambient temperature. While numerous novel metal hydride compounds…
Thermodynamic quantities of the hard-sphere system in the steady state with a small heat flux are calculated within the continuous media approach. Analytical expressions for pressure, internal energy, and entropy are found in the…
Phase stability, and the limits thereof, are a central concern of materials thermodynamics. However, the temperature limits of equilibrium liquid stability in chemical systems have only been widely characterized under constant (typically…
He-4 is known to become superfluid at very low temperatures. This effect is now generally accepted to be connected with BEC (Bose-Einstein Condensation). The dispersion relation of pressure waves in superfluid He-4 has been determined at…
$LaH_{10}$, as a member of hydrogen-rich superconductors, has a superconducting critical temperature of 250 K at high pressures, which exhibits the possibility of solving the long-term goal of room temperature superconductivity. Considering…