D-Dimensional Radiative Plasma: A Kinetic Approach

TL;DR

This paper extends the covariant kinetic approach for radiative plasma to D spatial dimensions, analyzing transport coefficients and fluid behavior, with implications for higher-dimensional cosmologies.

Contribution

It generalizes the kinetic theory of radiative plasma to D dimensions and evaluates transport coefficients explicitly, revealing dimension-independent fluid behavior.

Findings

Transport coefficients are explicitly derived in D dimensions.

The fluid behavior remains consistent regardless of the number of spatial dimensions.

Implications for higher-dimensional cosmological models are discussed.

Abstract

The covariant kinetic approach for the radiative plasma, a mixture of a relativistic moving gas plus radiation quanta (photons, neutrinos, or gravitons) is generalized to D spatial dimensions. The operational and physical meaning of Eckart's temperature is reexamined and the D-dimensional expressions for the transport coefficients (heat conduction, bulk and shear viscosity) are explicitly evaluated to first order in the mean free time of the radiation quanta. Weinberg's conclusion that the mixture behaves like a relativistic imperfect simple fluid (in Eckart's formulation) depends neither on the number of spatial dimensions nor on the details of the collisional term. The case of Thomson scaterring is studied in detail, and some consequences for higher dimensional cosmologies are also discussed.