On the derivation of the Landau-Lifshitz frame in relativistic kinetic theory

The Landau-Lifshitz frame has been widely used to represent the macroscopic quantities of relativistic hydrodynamics in the presence of the dissipative process. In this paper, we derive the Landau-Lifshitz frame in the near-equilibrium regime under self-contained assumptions that do not require comparison with the Eckart frame. And then we revisit the relativistic BGK model proposed by Anderson and Witting to provide an application example of the Landau-Lifshitz frame.

In-medium thermal conductivity and diffusion coefficients of a hot hadronic gas mixture

The relativistic kinetic theory approach has been employed to estimate for a hot mixture constituting of nucleons and pions, four transport coefficients that characterize heat flow and diffusion. Medium effects on the cross-section for binary collisions ([Formula: see text]) have been taken into consideration by incorporating self-energy corrections to modify the [Formula: see text] and [Formula: see text] meson propagators for [Formula: see text] interaction and the [Formula: see text] propagator for [Formula: see text] interaction. The temperature dependence of the various coefficients has been studied for several values of the baryon chemical potential.

The Energy-Momentum Tensor in Relativistic Kinetic Theory: The Role of the Center of Mass Velocity in the Transport Equations for Multicomponent Mixtures

Relativistic kinetic theory is applied to the study of the balance equations for relativistic multicomponent mixtures, comparing the approaches corresponding to Eckart’s and Landau–Lifshitz’s frames. It is shown that the concept of particle velocity relative to the center of mass of the fluid is essential to establish the structure of the energy-momentum tensor in both cases. Different operational definitions of the center of mass velocity lead either to the inclusion of heat in the energy-momentum tensor (particle/Eckart frame) or to strictly relativistic contributions to the diffusion fluxes (energy/Landau–Lifshitz frame). The results here obtained are discussed emphasizing the physical features regarding each approach.