Speaker
Description
Relativistic fluid theories derived from kinetic theory provide a consistent framework for describing transport processes in out-of-equilibrium systems. In this context, first-order perturbative solutions of the relativistic Boltzmann equation lead to constitutive equations that couple dissipative fluxes to both spatial and temporal derivatives of the state variables, as well as to the electromagnetic field. Moreover, kinetic theory provides explicit expressions for the corresponding transport coefficients and allows the verification of the second law of thermodynamics within the regime of validity of the approximation.
In this talk, the single-component gas general constitutive equations obtained from the microscopic theory are examined in order to clearly separate the effects of frame and representation first-order transformations in the presence of a weak electromagnetic field. Building upon this formulation, we then consider relativistic binary mixtures in a regime where direct and cross-collisions contribute at the same order. In this setting, cross effects naturally arise, and advances towards assessing their relevance for transport phenomena will be discussed. We further verify that Onsager's reciprocal relations and the second law of thermodynamics hold in a particular frame and show how these properties can be expressed in a frame-invariant manner, ensuring their validity independently of the hydrodynamic frame.