1,048 research outputs found
A scaling law for the dust cloud in radio frequency discharge under microgravity conditions
We employ the approximation of overlapped scattering potentials of charged
dust particles exposed to streaming ions to deduce the "equation of state" for
a stationary dust cloud in the radio frequency discharge apart from the void
dust boundary. The obtained equation defines the potential of a dust particle
as a function of the ion number density, the mass of a carrier gas atom, and
the electron temperature. A scaling law that relates the particle number
density to the particle radius and electron temperature in different systems is
formulated. Based on the proposed approach the radius of a cavity around a
large particle in the bulk of a cloud is estimated. The results of calculation
are in a reasonable agreement with the experimental data available in
literature.Comment: 10 pages, 7 figures, and 1 tabl
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
Peculiarities of momentum distribution functions of strongly correlated charged fermions
The new numerical version of the Wigner approach to quantum mechanics for
treatment thermodynamic properties of strongly coupled systems of particles has
been developed for extreme conditions, when analytical approximations obtained
in different kind of perturbation theories can not be applied. Explicit
analytical expression of the Wigner function has been obtained in linear and
harmonic approximations. Fermi statistical effects are accounted by effective
pair pseudopotential depending on coordinates, momenta and degeneracy parameter
of particles and taking into account Pauli blocking of fermions. The new
quantum Monte-Carlo method for calculations of average values of arbitrary
quantum operators has been proposed. Calculations of the momentum distribution
function of the degenerate ideal Fermi gas have been carried out for testing
the developed approach. Comparison of obtained momentum distribution function
of strongly correlated Coulomb systems of particles with Maxwell -- Boltzmann
and Fermi distributions shows the significant influence of interparticle
interaction both at small momenta and in the high energy quantum 'tails'.Comment: 14 pages, 6 captured figures. arXiv admin note: text overlap with
arXiv:1702.0409
Onset of cavity deformation upon subsonic motion of a projectile in a fluid complex plasma
We study deformation of a cavity around a large projectile moving with
subsonic velocity in the cloud of small dust particles. To solve this problem,
we employ the Navier--Stokes equation for a compressible fluid with due regard
for friction between dust particles and atoms of neutral gas. The solutions
shows that due to friction, the pressure of dust cloud at the boundary of the
cavity behind the projectile can become negative, which entails formation of a
microscopic void free from dust particles -- the cavity deformation.
Corresponding threshold velocity is calculated, which is found to decrease with
increasing cavity size. Measurement of such velocity makes it possible to
estimate the static pressure inside the dust cloud.Comment: 7 pages, 3 figure
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
Color path-integral Monte Carlo simulations of quark-gluon plasma
Thermodynamic properties of a strongly coupled quark-gluon plasma (QGP) of
constituent quasiparticles are studied by a color path-integral Monte Carlo
simulations (CPIMC). For our simulations we have presented QGP partition
function in the form of color path integral with new relativistic measure
instead of Gaussian one used in Feynman and Wiener path integrals. For
integration over color variable we have also developed procedure of sampling
color variables according to the group SU(3) Haar measure. It is shown that
this method is able to reproduce the available quantum lattice chromodynamics
(QCD) data
Correlation effects in partially ionized mass asymmetric electron-hole plasmas
The effects of strong Coulomb correlations in dense three-dimensional
electron-hole plasmas are studied by means of unbiased direct path integral
Monte Carlo simulations. The formation and dissociation of bound states, such
as excitons and bi-excitons is analyzed and the density-temperature region of
their appearance is identified. At high density, the Mott transition to the
fully ionized metallic state (electron-hole liquid) is detected. Particular
attention is paid to the influence of the hole to electron mass ratio on
the properties of the plasma. Above a critical value of about M=80 formation of
a hole Coulomb crystal was recently verified [Phys. Rev. Lett. {\bf 95}, 235006
(2005)] which is supported by additional results. Results are related to the
excitonic phase diagram of intermediate valent Tm[Se,Te], where large values of
have been observed experimentally.Comment: slightly modified and shortened paper to appear in Physical Review E;
contains more detailed presentation of theory (appendices
Equation of state of strongly coupled quark--gluon plasma -- Path integral Monte Carlo results
A strongly coupled plasma of quark and gluon quasiparticles at temperatures
from to is studied by path integral Monte Carlo simulations.
This method extends previous classical nonrelativistic simulations based on a
color Coulomb interaction to the quantum regime. We present the equation of
state and find good agreement with lattice results. Further, pair distribution
functions and color correlation functions are computed indicating strong
correlations and liquid-like behavior
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