Related papers: Reducing the hydrogen content in liquid helium
Methanol is a potentially important impurity in subsurface oceans on Titan and Enceladus. We report measurements of the freezing of methanol-water samples at pressures up to 350~MPa using a volumetric cell with sapphire windows. For low…
When fragile molecules such as glycine, polyglicine, alkanes, and alkanethiols are embedded in liquid helium nanodroplets, electron-impact ionization of the beam leads to fragmentation which is as extensive as that of isolated gas-phase…
Superfluid helium is a prototypical quantum liquid. As such, it has been a prominent platform for the study of quantum many body physics. More recently, the outstanding mechanical and optical properties of superfluid helium, such as low…
Hydrogen is widely regarded as a cornerstone of future low-carbon energy technologies, yet the lack of safe, efficient, and reversible solid-state storage materials remains a major barrier to its large-scale deployment. Although porous…
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…
We describe experiments where 2D atomic hydrogen gas is compressed thermally at a small "cold spot" on the surface of superfluid helium and detected directly with electron-spin resonance. We reach surface densities up to 5e12 1/cm^2 at…
We consider the thermal properties of cold, dense clouds of molecular hydrogen and atomic helium. For cloud masses below 10^-1.7 Msun, the internal pressure is sufficient to permit the existence of particles of solid or liquid hydrogen at…
The striking anomalies in physical properties of supercooled water that were discovered in the 1960-70s, remain incompletely understood and so provide both a source of controversy amongst theoreticians, and a stimulus to experimentalists…
A phenomenological criterion for the superfluid transition is proposed, which is similar to the Lindemann criterion for the crystal melting. Then we derive a new formula for the critical temperature, relating $T_{\lambda}$ to the mean…
A reliable process for compressing hydrogen and for removing all contaminants is that of the metal hydride thermal compression. The use of metal hydride technology in hydrogen compression applications though, requires thorough structural…
Molecular beam experiments that use low-temperature bolometers as (energy-) detectors are well suited to the study of physisorption and recombination of hydrogen on low-temperature surfaces. Experiments where this technique is combined with…
The flow velocity of solid 4He through a porous membrane frozen into a crystal has been measured in the temperature interval 0.1 - 1.8 K. A flat capacitor consisting of a metalized plastic porous membrane and a bulk electrode is applied and…
We present transport measurements of electrons on the surface of liquid helium in a microchannel device in which a constriction may be formed by a split-gate electrode. The surface electron current passing through the microchannel first…
As helium-4 is cooled below 2.17 K it undergoes a phase transition to a fundamentally new state of matter known as a superfluid which supports flow without viscosity. This type of dissipationless transport can be observed by forcing helium…
Using an optical interferomertric method, the homogeneous cavitation density of superfluid helium at $T=0.96\,$K is measured and found to be $\rho_{cav}=0.1338\pm0.0002\rm\,g.cm^{-3}$. A well established equation of state for liquid helium…
We report the successful operation of a functional pixel detector with gaseous helium cooling. Using an accurate mock-up beforehand, the cooling was validated. We use a miniature turbo compressor to propel the helium at $2\,g/s$ under…
Preparing and detecting spatially extended quantum superpositions of a massive object comprises an important fundamental test of quantum theory. These quantum states are extremely fragile and tend to quickly decay into incoherent mixtures…
Hydrogen is the most abundant element in the universe, and its properties under conditions of high temperature and pressure are crucial to understand the interior of of large gaseous planets and other astrophysical bodies. At ultra high…
Hydrogen in its metallic form is the most common material in our solar system, found under the extreme pressure and temperature conditions found in giant planets. Such conditions are inaccessible to experiment and consequently, theoretical…
The study of the formation of molecular hydrogen on low temperature surfaces is of interest both because it allows to explore elementary steps in the heterogeneous catalysis of a simple molecule and because of the applications in…