Results 21 to 30 of about 3,788,726 (334)

Gauge-ready formulation of the cosmological kinetic theory in generalized gravity theories [PDF]

, 2001
We present cosmological perturbations of kinetic components based on relativistic Boltzmann equations in the context of generalized gravity theories. Our general theory considers an arbitrary number of scalar fields generally coupled with the gravity, an
A. Challinor, A. Challinor, A. Challinor, A. Kosowsky, A. Lewis, A. Rebhan, A. Rebhan, A.A. Penzias, A.A. Starobinsky, A.D. Sakharov, A.G. Doroshkevich, A.H. Guth, A.V. Zakharov, A.V. Zakharov, A.V. Zakharov, A.V. Zakharov, A.V. Zakharov, A.V. Zakharov, A.V. Zakharov, A.V. Zakharov, B. Whitt, C. Ma, D. Kazanas, D.H. Lyth, D.S. Salopek, E. Gliner, E. Newman, E.M. Lifshitz, E.M. Lifshitz, E.R. Harrison, E.T. Vishniac, G. Dautcourt, G. Dautcourt, G. Efstathiou, G. Efstathiou, G. Magnano, G.F.R. Ellis, H. Kodama, H. Kodama, H. Nariai, Hyerim Noh, I.H. Gilbert, J. Ehlers, J. Hwang, J. Hwang, J. Hwang, J. Hwang, J. Hwang, J. Hwang, J. Hwang, J. Silk, J.M. Bardeen, J.M. Stewart, J.M. Stewart, J.R. Bond, J.R. Bond, J.R. Bond, Jai-chan Hwang, M. Bucher, M. Kamionkowski, M. Kasai, M. Zaldarriaga, M. Zaldarriaga, M.L. Wilson, M.L. Wilson, N. Gouda, N. Gouda, N. Gouda, N. Sugiyama, N. Sugiyama, P. de Bernardis, P.J.E. Peebles, P.J.E. Peebles, P.J.E. Peebles, P.T.P. Viana, R. Durrer, R. Maartens, R.A. Sunyaev, R.H. Dicke, R.K. Sachs, R.K. Schaefer, R.W. Lindquist, S. Dodelson, S. Hanany, S. Seager, S.W. Hawking, T. Gebbie, U. Seljak, U. Seljak, U. Seljak, V. Faraoni, V.N. Lukash, V.N. Lukash, W. Hu, W. Hu, W. Hu, W. Hu, W. Hu, W. Israel   +98 more
core   +2 more sources

Leptogenesis with heavy neutrino flavours: from density matrix to Boltzmann equations [PDF]

, 2011
Leptogenesis with heavy neutrino flavours is discussed within a density matrix formalism. We write the density matrix equation, describing the generation of the matter-antimatter asymmetry, for an arbitrary choice of the right-handed (RH) neutrino masses.
Steve Blanchet, David A. Jones, P. Bari, L. Marzola   +3 more
semanticscholar   +1 more source

Baryon Physics and Tight Coupling Approximation in Boltzmann Codes

Universe, 2019
We provide two derivations of the baryonic equations that can be straightforwardly implemented in existing Einstein−Boltzmann solvers. One of the derivations begins with an action principle, while the other exploits the conservation of the stress ...
Masroor C. Pookkillath, Antonio De Felice, Shinji Mukohyama   +2 more
doaj   +1 more source

Hybrid Lattice Boltzmann Model for Nonlinear Diffusion and Image Denoising

Mathematics, 2023
In the present paper, a novel approach for image denoising based on the numerical solution to the nonlinear diffusion equation is proposed. The Perona–Malik-type equation is solved by employing a hybrid lattice Boltzmann model with five discrete ...
Oleg Ilyin
doaj   +1 more source

Derivation of Covariant Dissipative Fluid Dynamics in the Renormalization-group Method [PDF]

, 2006
We derive generic relativistic hydrodynamical equations with dissipative effects from the underlying Boltzmann equation in a mechanical and systematic way on the basis of so called the renormalization-group (RG) method.
Kunihiro, T., Ohnishi, K., Tsumura, K.
core   +2 more sources

A Multiple-Grid Lattice Boltzmann Method for Natural Convection under Low and High Prandtl Numbers

Fluids, 2021
A multi-distribution lattice Boltzmann Bhatnagar–Gross–Krook (BGK) model with a multiple-grid lattice Boltzmann (MGLB) model is proposed to efficiently simulate natural convection over a wide range of Prandtl numbers. In this method, different grid sizes
Seyed Amin Nabavizadeh, Himel Barua, Mohsen Eshraghi, Sergio D. Felicelli   +3 more
doaj   +1 more source

Mesoscopic Simulation of the Two-Component System of Coupled Sine-Gordon Equations with Lattice Boltzmann Method

Entropy, 2019
In this paper, a new lattice Boltzmann model for the two-component system of coupled sine-Gordon equations is presented by using the coupled mesoscopic Boltzmann equations.
Demei Li, Huilin Lai, Chuandong Lin
doaj   +1 more source

Absence of Hall effect due to Berry curvature in phase space

Scientific Reports, 2021
Transverse current due to Berry curvature in phase space is formulated based on the Boltzmann equations with the semiclassical equations of motion for an electron wave packet.
Takehito Yokoyama
doaj   +1 more source

On kinetic Boltzmann equations and related hydrodynamic flows with dry viscosity [PDF]

Opuscula Mathematica, 2007
A two-component particle model of Boltzmann-Vlasov type kinetic equations in the form of special nonlinear integro-differential hydrodynamic systems on an infinite-dimensional functional manifold is discussed.
Nikolai N. Bogoliubov (Jr.), Denis L. Blackmore, Valeriy Hr. Samoylenko, Anatoliy K. Prykarpatsky   +3 more
doaj  

Turbulence through the Spyglass of Bilocal Kinetics

Entropy, 2018
In two recent papers we introduced a generalization of Boltzmann’s assumption of molecular chaos based on a criterion of maximum entropy, which allowed setting up a bilocal version of Boltzmann’s kinetic equation.
Gregor Chliamovitch, Yann Thorimbert
doaj   +1 more source