110 research outputs found
Phase Transition in Strongly Degenerate Hydrogen Plasma
Direct fermionic path-integral Monte-Carlo simulations of strongly coupled
hydrogen are presented. Our results show evidence for the hypothetical plasma
phase transition. Its most remarkable manifestation is the appearance of
metallic droplets which are predicted to be crucial for the electrical
conductivity allowing to explain the rapid increase observed in recent shock
compression measurments.Comment: 1 LaTeX file using jetpl.cls (included), 5 ps figures. Manuscript
submitted to JETP Letter
Hole crystallization in semiconductors
When electrons in a solid are excited to a higher energy band they leave
behind a vacancy (hole) in the original band which behaves like a positively
charged particle. Here we predict that holes can spontaneously order into a
regular lattice in semiconductors with sufficiently flat valence bands. The
critical hole to electron effective mass ratio required for this phase
transition is found to be of the order of 80.Comment: accepted for publication in J. Phys. A: Math. Ge
Thermodynamic Properties of Correlated Strongly Degenerate Plasmas
An efficient numerical approach to equilibrium properties of strongly coupled
systems which include a subsystem of fermionic quantum particles and a
subsystem of classical particles is presented. It uses an improved path
integral representation of the many-particle density operator and allows to
describe situations of strong coupling and strong degeneracy, where analytical
theories fail. A novel numerical method is developed, which allows to treat
degenerate systems with full account of the spin scatistics. Numerical results
for thermodynamic properties such as internal energy, pressure and pair
correlation functions are presented over a wide range of degeneracy parameter.Comment: 8 pages, 4 figures, uses sprocl.sty (included) to be published in
"Progress in Nonequilibrium Green's functions", M. Bonitz (Ed.), World
Scientific 200
Thermodynamic properties and electrical conductivity of strongly correlated plasma media
We study thermodynamic properties and the electrical conductivity of dense
hydrogen and deuterium using three methods: classical reactive Monte Carlo
(REMC), direct path integral Monte Carlo (PIMC) and a quantum dynamics method
in the Wigner representation of quantum mechanics. We report the calculation of
the deuterium compression quasi-isentrope in good agreement with experiments.
We also solve the Wigner-Liouville equation of dense degenerate hydrogen
calculating the initial equilibrium state by the PIMC method. The obtained
particle trajectories determine the momentum-momentum correlation functions and
the electrical conductivity and are compared with available theories and
simulations
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