Responses of a quantum plasma

Abstract

In this chapter QED is used to calculated the response tensors of a plasma. The basic ideas used here for including the medium are twofold. First, the propagators in vacuo, identified as vacuum expectation values, are re-interpreted as expectation values for the medium. In the statistical averages, the electrons and positrons are described in terms of their occupation numbers, nsε (p), and photons in a mode M by their occupation number NM (k). Second, the statistical averages are applied to diagrams with closed loops that represent radiative corrections in QED. In particular, the bubble diagram in QED leads to the vacuum polarization tensor after regularization, and its statistical average gives an additional contribution that corresponds to the linear response tensor for the medium. © 2008 Springer-Verlag New York.