Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hydrodynamic Modes of Homogeneous and Isotropic Fluids   Relativistic fluids are Lorentz invariant, and a non-relativistic limit of
such fluids leads to the well-known Navier-Stokes equation. However, for fluids
moving with respect to a reference system, or in critical systems with generic
dynamical exponent z, the assumption of Lorentz invariance (or its
non-relativistic version) does not hold. We are thus led to consider the most
general fluid assuming only homogeneity and isotropy and study its
hydrodynamics and transport behaviour. Remarkably, such systems have not been
treated in full generality in the literature so far. Here we study these
equations at the linearized level. We find new expressions for the speed of
sound, corrections to the Navier-Stokes equation and determine all dissipative
and non-dissipative first order transport coefficients. Dispersion relations
for the sound, shear and diffusion modes are determined to second order in
momenta. In the presence of a scaling symmetry with dynamical exponent z, we
show that the sound attenuation constant depends on both shear viscosity and
thermal conductivity.

31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con