2016/02/29 by E. Molnár, E. Molnar, H. Niemi +2 · 87 citations
Mathematics · Physics and Astronomy · #Anisotropy #Boltzmann equation #Classical mechanics #Cosmology and Gravitation Theories #Dissipative system #Distribution function #Gas Dynamics and Kinetic Theory #High-Energy Particle Collisions Research #Isotropy #Mathematical physics #Momentum (technical analysis) #Physics #Quantum mechanics #Velocity Moments #hep-ph #nucl-th #physics.flu-dyn
paper · pdf · doi:10.1103/physrevd.93.114025
published in Physical review. D/Physical review. D. 93(11) (American Physical Society) · 52 pages; Abstract slightly changed; new references and new paragraph added
openalex publication_date 2016/06/22 · arxiv created 2016/06/23 · arxiv updated 2016/06/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Fluid-dynamical equations of motion can be derived from the Boltzmann equation in terms of an expansion around a single-particle distribution function which is in local thermodynamical equilibrium, i.e., isotropic in momentum space in the rest frame of a fluid element. However, in situations where the single-particle distribution function is highly anisotropic in momentum space, such as the initial stage of heavy-ion collisions at relativistic energies, such an expansion is bound to break down. Nevertheless, one can still derive a fluid-dynamical theory, called anisotropic dissipative fluid dynamics, in terms of an expansion around a single-particle distribution function, \stackrel^f0k, which incorporates (at least parts of) the momentum anisotropy via a suitable parametrization. We construct such an expansion in terms of polynomials in energy and momentum in the direction of the anisotropy and of irreducible tensors in the two-dimensional momentum subspace orthogonal to both the fluid velocity and the direction of the anisotropy. From the Boltzmann equation we then derive the set of equations of motion for the irreducible moments of the deviation of the single-particle distribution function from \stackrel^f0k. Truncating this set via the 14-moment approximation, we obtain the equations of motion of anisotropic dissipative fluid dynamics.