Related papers: Structural Phase Transition at High Temperatures i…
The methyl groups in hexamethylbenzene C$_6$(CH$_3$)$_6$ become magnetically ordered at the molecular level below 118 K. This is also near the temperature at which the system structurally transitions from triclinic to a unique near-cubic…
As the simplest element in nature, unraveling the phase diagram of hydrogen is a primary task for condensed matter physics. As conjectured many decades ago, in the low-temperature and high-pressure part of the phase diagram, solid hydrogen…
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,…
A calculation of the rotational S$_0$(0) frequencies in high pressure solid para-hydrogen is performed. Convergence of the perturbative series at high density is demonstrated by the calculation of second and third order terms. The results…
We use the diffusion quantum Monte Carlo (DMC) method to calculate the ground state phase diagram of solid molecular hydrogen and examine the stability of the most important insulating phases relative to metallic crystalline molecular…
We study the electronic excitation spectra in solid molecular hydrogen (phase I) at ambient temperature and 5-90 GPa pressures using Quantum Monte Carlo methods and Many-Body Perturbation Theory. In this range, the system changes from a…
Perturbed angular correlation spectroscopy combined with $ab-initio$ electronic structure calculations is used to unravel the structural phase transition path from the low-temperature polar structure to the high-temperature structural phase…
The high critical superconducting temperatures ($T_c$s) of metal hydride phases with clathrate-like hydrogen networks have generated great interest. Herein, we employ the Density Functional Theory-Chemical Pressure (DFT-CP) method to…
We compute the thermodynamic phase diagram of seventeen elemental metals with hexagonal close-packed (hcp), face-centered cubic (fcc), and body-centered cubic (bcc) crystal structures using finite-temperature density functional theory.…
Extensive Path Integral Monte Carlo simulations of condensed para-Hydrogen in two dimensions at low temperature have been carried out. In the zero temperature limit, the system is a crystal at equilibrium, with a triangular lattice…
Firstly, I give a brief summary of the current understanding of QCD below and near $T_c$ (the critical temperature of the chiral transition). Some emphases are put on the qualitative difference between the Yukawa regime ($T \sim 0)$ and the…
The transition of a warm dense fluid hydrogen from insulator to a conducting state at pressures of the order of 20-300 GPa and temperatures of 1000-5000 K has been the subject of active scientific research over the past few decades. The use…
We present results of a theoretical study of para-hydrogen and ortho-deuterium clusters at low temperature (0.5 K < T < 3.5 K), based on Path Integral Monte Carlo simulations. Clusters of size up to N=21 para-hydrogen molecules are nearly…
We present results predicting experimentally measurable structural quantities from molecular dynamics studies of hydrogen. In doing this, we propose a paradigm shift for experimentalists -- that the predictions from such calculations should…
We perform molecular dynamics simulations driven by accurate Quantum Monte Carlo forces on dense liquid hydrogen. Recently it has been reported a complete atomization transition between a mixed-atomic liquid and a completely dissociated…
For a long time, there have been huge discrepancies between different models and experiments concerning the liquid-liquid phase transition (LLPT) in dense hydrogen. In this work, we present the results of extensive calculations of the LLPT…
Restricted path integral Monte Carlo simulations are used to calculate the equilibrium properties of hydrogen in the density and temperature range of $9.83 \times 10^{-4}\rm \leq \rho \leq 0.153 \rm gcm^{-3}$ and $5000 \leq T \leq 250 000…
The high-pressure II-III phase transition in solid hydrogen is investigated using the random phase approximation and diffusion Monte Carlo. Good agreement between the methods is found confirming that an accurate treatment of exchange and…
Temperature dependent electrical resistivity, crystal structure and heat capacity measurements reveal a resistivity drop and metal to semiconductor transition corresponding to first order structural phase transition near 400 K in Ca3Co4O9.…
Phase I of hydrogen has several peculiarities. Despite having a close-packed crystal structure, it is less dense than either the low temperature Phase II or the liquid phase. At high pressure, it transforms into either phase III or IV,…