Dielectric Function and Transport Coefficients in Strongly Coupled Plasmas

Abstract

A consistent unified approach to the dielectric function as well as the dc conductivity is presented. A standard approach to the dc electrical conductivity is given by the ChapmanEnskog approach. In dense plasmas, linear response theory has been worked out to relate the dc conductivity to equilibrium correlation functions which can be evaluated using the method of thermodynamic Green functions. The dielectric function can also be expressed in terms of equilibrium correlation functions, but a simple perturbative treatment to include collision effects is not possible near the point because an essential singularity arises in zeroth order. Different improvements are known to go beyond the well-known RPA result. In the static limit, local field corrections have been discussed extensively, and the dynamical behavior of the corrections to the RPA in the long-wavelength limit was investigated in the timedependent mean field theory neglecting damping effects, see also Ref. [6] for the strong coupling case. At arbitrary and approximations are made on the basis of sum rules for the lowest moments. However, these approximations cannot give an unambiguous expression for in the entire space. Within a generalized linear response theory, the polarization function is related to equilibrium correlation functions for nonideal plasmas. Applying perturbation theory, thermodynamic Green functions are evaluated in Born approximation. Improvements are possible using diagram techniques and partial summations. A promising alternative to evaluate equilibrium correlation functions in strongly coupled plasmas is given by molecular dynamics simulations, see the related contributions to this Conference.