Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 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.

3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
2
The categories of this paper are: math