Biomedical subjects

M S Murillo

Publications and source records attributed to M S Murillo.

4 recordsLinked to original sources

PubMed2003

Gibbs-Bogolyubov inequality and transport properties for strongly coupled Yukawa fluids.

The Gibbs-Bogolyubov inequality is used to establish a mapping between the Yukawa system and both the hard-sphere and the one-component reference systems. The transport coefficients of self-diffusion, shear viscosity, and thermal conductivity are computed for the Yukawa fluid using known properties of the reference systems. Comparisons are made with simulation results. For sufficiently strong screening, the hard-sphere reference system yields a lower upper bound of the Yukawa Helmholtz free energy and a better estimate of the Yukawa transport coefficients.

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PubMed2002

Dense plasma temperature equilibration in the binary collision approximation.

Temperature equilibration in dense, strongly coupled plasmas has been investigated without most of the usual simplifying assumptions. A quantum kinetic approach is used that accounts for strong electron-ion collisions through an exact T-matrix treatment of the scattering cross section using a screened interaction. Our results reveal the accuracy of the usual Spitzer formula for Coulomb logarithms larger than about three. Moreover, a simple model based on hyperbolic orbits yields surprisingly accurate results. We also have included equation of state effects to describe realistic plasmas.

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PubMed2001

Using Fermi statistics to create strongly coupled ion plasmas in atom traps.

We investigate the possibility of forming a strongly coupled ion plasma from a cold atomic gas. We show that rapid ion heating occurs as correlations develop from the initial disordered configuration. This heating severely reduces the Coulomb coupling of the final configuration, although the final Coulomb coupling can be maximized by introducing order into the initial atomic gas. We show that such order can be introduced into the initial state by employing a degenerate Fermi gas whereby the Pauli hole mimics the Coulomb hole. The corresponding initial state correlations can enhance the Coulomb coupling in the final state by orders of magnitude.

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PubMed2001

Shear viscosity of strongly coupled Yukawa systems on finite length scales.

The Yukawa shear viscosity has been calculated using nonequilibrium molecular dynamics. Near the viscosity minimum, we find exponential decay consistent with the Navier-Stokes equation, with significant deviations on finite length scales for larger viscosity values. The viscosity is determined to be nonlocal on a scale length consistent with the correlation length, revealing the length scales necessary for obtaining transport coefficients in the hydrodynamic limit by nonequilibrium molecular dynamics methods. Our results are quasiuniversal with respect to excess entropy for excess entropies well below unity.

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