Charged-boson fluid in two and three dimensions

We examine various properties of the two- and three-dimensional plasma of charged bosons over an extensive range of densities, especially in the previously less studied low-density regime using a microscopic, variational approach. We calculate the ground-state structure and energetics and compare both our analytical and numerical results with earlier theoretical work. Throughout the entire density regime investigated, good agreement with the results of several Monte Carlo calculations is obtained. Triplet correlations are found to be important for the consistency of the equation of state at high densities. To study excitations we then allow for time-dependent interparticle correlations. Special attention is paid to the question of a microscopic justification for the "local-field factor," and the consistency demands imposed by sum rules on microscopic excitation theories. Results for the static dielectric function ε(k,0) and the dynamic structure function S(k,ω) are presented in three and two dimensions.