Article
Mathematics
Sebastiano Pennisi, Rita Enoh Tchame, Marcel Obounou
Summary: This paper studies Maxwell's equations in materials and Euler equations using new knowledge about polyatomic gases. A supplementary conservation law is imposed, leading to a restriction on the law linking magnetic and electric fields to force densities. To simplify the problem, a new symmetric hyperbolic set of equations is presented using unconstrained variables. The solutions of this new set of equations, satisfying the initial constraints, can restore the previous constrained set and maintain overt covariance.
Article
Physics, Multidisciplinary
Gabriel S. Rocha, Gabriel S. Denicol, Jorge Noronha
Summary: The widely used relaxation time approximation to the relativistic Boltzmann equation has flaws when energy-dependent relaxation time or general matching conditions are considered. A new approximation is proposed to address these issues while maintaining basic properties of the linearized Boltzmann collision operator. The correction is shown to affect transport coefficients such as bulk viscosity and particle diffusion.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
Alex Pandya, Elias R. Most, Frans Pretorius
Summary: This study presents the first numerical analysis of relativistic hydrodynamics with ideal gas microphysics. It explores the impact of different hydrodynamic frames on the behavior of various physical solutions, using the methods and constraints provided by the BDNK theory.
Article
Astronomy & Astrophysics
Esteban Calzetta
Summary: A simple model was used to study nonlinear phenomena in a real relativistic fluid, focusing on new types of behavior without nonrelativistic equivalents, such as an entropy cascade driven by fluctuations in the theory's tensor degrees of freedom. The von Karman-Howarth equations for this kind of turbulence were derived, along with considerations of correlations corresponding to fully developed turbulence.
Article
Physics, Multidisciplinary
Maxime Debiossac, Martin Luc Rosinberg, Eric Lutz, Nikolai Kiesel
Summary: The experimental study investigates the statistical properties of a nanoparticle in an optically trapped system with time-delayed feedback control, and shows that the acausality of the system is clearly exhibited in the long-time limit of the fluctuation relations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
J. Guemez, J. A. Mier
Summary: Two thermodynamic processes, including the launching of a projectile by forces produced by chemical reactions and the Joule-Kelvin process implemented on a conveyor belt, are analyzed using a relativistic four-vector fundamental equation formalism. The corresponding equations in different reference frames are obtained through Lorentz transformation, satisfying Einstein's principle of relativity. Non-mechanical energies are assigned linear momentum and their variations are considered in Newton's second law equation, taking into account relativistic non-simultaneity and conveyor belt effects. It is shown that entropy variations and fuel consumption are frame independent in relativistic thermodynamics.
Article
Physics, Multidisciplinary
Jorge Noronha, Michal Spalinski, Enrico Speranza
Summary: This study presents a new theory of second-order viscous relativistic hydrodynamics without imposing frame conditions on the choice of hydrodynamic variables, and explicitly provides conditions for causality and stability in the conformal regime. By considering Bjorken flow solutions, variables that make a hydrodynamic attractor manifest are identified.
PHYSICAL REVIEW LETTERS
(2022)
Article
Green & Sustainable Science & Technology
A. Molina-Salas, S. Longo, M. Clavero, A. Monino
Summary: This research focuses on the dynamic similarity problem of Oscillating Water Column (OWC) devices and examines the influence of scale effects on thermodynamic processes. By using non-equilibrium thermodynamics, the study reveals the importance of non-equilibrium states as the scale approaches the size of the prototype, with consequences on performance.
Article
Astronomy & Astrophysics
Fabio S. Bemfica, Marcelo M. Disconzi, Jorge Noronha, Robert J. Scherrer
Summary: We investigate the out-of-equilibrium dynamics of viscous fluids in a spatially flat Friedmann-Lemaitre-Robertson-Walker cosmology using the most general causal and stable viscous energy-momentum tensor defined at first order in spacetime derivatives. In this new framework, a pressureless viscous fluid can evolve to an asymptotic future solution with a constant Hubble parameter and vanishing equilibrium energy density, even without a cosmological constant. This behavior is a consequence of causality in first-order theories of relativistic fluid dynamics and is consistent with Einstein's equations.
Article
Astronomy & Astrophysics
C. Brito, G. S. Denicol
Summary: This article discusses the linear causality and stability of third-order fluid dynamics, proposing a modification to ensure linear causality and stability in the linear regime. It emphasizes the importance of transport coefficients satisfying specific conditions for this to occur.
Article
Physics, Multidisciplinary
Fabio S. Bemfica, Marcelo M. Disconzi, Vu Hoang, Jorge Noronha, Maria Radosz
Summary: New constraints have been identified for Israel-Stewart-like theories of fluid dynamics to be causal far from equilibrium. Sufficient conditions have also been presented to ensure causality, local existence, and uniqueness of solutions in these theories. The findings provide fundamental constraints on the magnitude of viscous corrections in fluid dynamics far from equilibrium, without simplifying symmetry or near-equilibrium assumptions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
Rajesh Biswas, Sukanya Mitra, Victor Roy
Summary: In this article, a first-order, stable, and causal relativistic hydrodynamic theory is derived from the microscopic kinetic equation using the gradient expansion technique. The general frame, introduced from arbitrary matching conditions for hydrodynamic fields, and the momentum-dependent relaxation time approximation (MDRTA) are crucial in producing the essential field corrections for a causal and stable first-order relativistic theory.
Article
Astronomy & Astrophysics
T. Celora, N. Andersson, I Hawke, G. L. Comer
Summary: Researchers have developed a new covariant framework for filtering/averaging in the study of turbulent fluid dynamics, utilizing the fibration of spacetime associated with fluid elements and Fermi coordinates for analysis. The derived resolved equations address the effective dissipative terms due to coarse-graining, with particular focus on the thermodynamical interpretation. Additionally, a new closure scheme inspired by recent progress in modeling dissipative relativistic fluids has been proposed and its linear stability demonstrated.
Article
Astronomy & Astrophysics
Alex Pandya, Frans Pretorius
Summary: The first numerical solutions of the causal, stable relativistic Navier-Stokes equations formulated by BDNK are presented for conformal fluid in Minkowski spacetime. Comparisons are made with solutions obtained using the MIS formalism, showing good agreement for low viscosity but differences in regions with large gradients at high viscosity. The transient violation of weak energy condition in BDNK solutions converges towards a hydrodynamic regime, resembling an approach to a universal attractor. Smooth resolution of arbitrarily strong shockwaves is achieved when employing a hydrodynamic frame with maximum characteristic speed of the BDNK system as the speed of light or higher. Uncertainty remains regarding the well-posedness of discontinuous initial data for the BDNK system, particularly in the shock tube problem.
Article
Astronomy & Astrophysics
Jan A. Fotakis, Etele Molnar, Harri Niemi, Carsten Greiner, Dirk H. Rischke
Summary: In this paper, multicomponent relativistic second-order dissipative fluid dynamics is derived from the Boltzmann equations using the method of moments. The resulting fluid-dynamical equations are formally similar to those of a single-component system, but with different thermodynamic relations and transport coefficients.
Article
Astronomy & Astrophysics
Souvik Pramanik, Sudipta Das, Subir Ghosh
Article
Astronomy & Astrophysics
Sudipta Das, Subir Ghosh, Jan-Willem Van Holten, Supratik Pal
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2011)
Article
Physics, Multidisciplinary
Sudipta Das, Subir Ghosh
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2009)
Article
Astronomy & Astrophysics
Sudipta Das, Subir Ghosh
MODERN PHYSICS LETTERS A
(2011)
Article
Astronomy & Astrophysics
Sudipta Das, Subir Ghosh
Article
Astronomy & Astrophysics
Sudipta Das, Dibakar Roychowdhury
Article
Astronomy & Astrophysics
Sudipta Das, Souvik Pramanik
Article
Physics, Multidisciplinary
Sudipta Das, Subir Ghosh, Salvatore Mignemi
Article
Physics, Mathematical
Sudipta Das, Souvik Pramanik, Subir Ghosh
SYMMETRY INTEGRABILITY AND GEOMETRY-METHODS AND APPLICATIONS
(2014)
Article
Physics, Particles & Fields
Sudipta Das, Subir Ghosh, Jan-Willem van Holten, Supratik Pal
JOURNAL OF HIGH ENERGY PHYSICS
(2009)
Correction
Physics, Particles & Fields
Sudipta Das, Subir Ghosh, Jan-Willem van Holten, Supratik Pal
JOURNAL OF HIGH ENERGY PHYSICS
(2011)
