Related papers: Anomalous melting behavior of solid hydrogen at hi…
Structural and superfluid properties of para-Hydrogen clusters of size up to N=40 molecules, are studied at low temperature (0.5 K < T < 4 K) by Path Integral Monte Carlo simulations. The superfluid fraction displays an interesting,…
The hydrogen phase diagram has a number of unusual features which are generally well reproduced by density functional calculations. Unfortunately, these calculations fail to provide good physical insights into why those features occur. In…
The melting temperature ($T_m$) of a solid is generally determined by the pressure applied to it, or indirectly by its density ($n$) through the equation of state. This remains true even for helium solids\cite{wilk:67}, where quantum…
Most water in the universe may be superionic, and its thermodynamic and transport properties are crucial for planetary science but difficult to probe experimentally or theoretically. We use machine learning and free energy methods to…
We report molecular dynamics simulations of a hydrophobic polymer-chain in aqueous solution between $260 {K}$ and $420 {K}$ at pressures of $1 {bar}$, $3000 {bar}$, and $4500 {bar}$. The simulations reveal a hydrophobically collapsed state…
Water and hydrogen at high pressure make up a substantial fraction of the interiors of giant planets. Using ab initio random structure search methods we investigate the ground-state crystal structures of water, hydrogen, and hydrogen-oxygen…
A series of electronic and structural transitions are predicted in molten lithium from first principles. A new phase with tetrahedral local order characteristic of $sp^3$ bonded materials and poor electrical conductivity is found at…
The ab initio calculations suggest that the superconducting state in CaH6 under the pressure at 150 GPa has the highest critical temperature among the examined hydrogen-rich compounds. For this reason, the relevant thermodynamic parameters…
Elucidating the phase diagram of solid hydrogen is a key objective in condensed matter physics. Several decades ago, it was proposed that at low temperatures and high pressures, solid hydrogen would be a metal with a high superconducting…
The liquid-gas phase transition in hot asymmetric nuclear matter is studied within density-dependent relativistic mean-field models where the density dependence is introduced according to the Brown-Rho scaling and constrained by available…
We study water-hydrogen mixtures under planetary interior conditions using ab initio molecular dynamics simulations. We determine the thermodynamic properties of various water-hydrogen mixing ratios at temperatures of 2000 and 6000 K for…
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…
We consider the quantum melting of a two-dimensional flux lattice at temperature T = 0 in the ``superclean limit.'' In this regime, we find that vortex motion is dominated by the Magnus force. A Lindemann criterion predicts melting when…
In their recent work Dias and Silvera (Science 2017) claim to have observed the Wigner-Huntington transition of hydrogen to a metallic state (MH) at a pressure of 495 GPa at low temperatures. The evidence for this transition is based on a…
We present an accurate study of the static-nucleus electronic energy band gap of solid molecular hydrogen at high pressure. The excitonic and quasiparticle gaps of the $C2/c$, $Pc$, $Pbcn$, and $P6_3/m$ structures at pressures of 250, 300,…
We investigate the three-phase coexistence line of ethane (C$_2$H$_6$) hydrate through molecular dynamics simulations using the direct coexistence approach. In this framework, C$_2$H$_6$ sI hydrate, aqueous, and pure guest phases are…
Following the idea that hydrogen-rich compounds might be high-T$_c$ superconductors at high pressures, and the very recent breakthrough in predicting and synthesizing hydrogen sulfide with record-high T$_c$ = 203 K, ab initio evolutionary…
Various condensed phases of water, spanning from the liquid state to multiple ice phases, have been systematically investigated under extreme conditions of pressure and temperature to delineate their stability boundaries. This study focuses…
We study the high-pressure melting behavior of titanium using laser-driven shock compression with in situ femtosecond x-ray diffraction and molecular-dynamics simulations based on a machine-learned interatomic potential. The MD simulations…
Liquid helium under negative pressure represents a unique possibility for studying the macroscopic quantum nucleation phenomena in condensed media. We analyze the quantum cavitation rate of single electron bubbles at low temperatures down…