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Conditional elimination of degrees of freedom is shown to lead to an exact expression for the rate of turbulent energy dissipation in terms of a renormalized viscosity and a correction. The correction is neglected on the basis of a previous…

Condensed Matter · Physics 2009-10-31 C. Johnston , W. D. McComb

The diffusion equation is the primary tool to study the movement dynamics of a free Brownian particle, but when spatial heterogeneities in the form of permeable interfaces are present, no fundamental equation has been derived. Here we…

Statistical Mechanics · Physics 2022-09-14 Toby Kay , Luca Giuggioli

The first-order Fermi acceleration process at an ultra-relativistic shock wave is expected to create a particle spectrum with the unique asymptotic spectral index sigma_{gamma >> 1} approximately 2.2. Below, we discuss this result and…

Astrophysics · Physics 2011-05-23 M. Ostrowski , J. Bednarz

Procedures for time-ordering the covariance function, as given in a previous paper (K. Kiyani and W.D. McComb Phys. Rev. E 70, 066303 (2004)), are extended and used to show that the response function associated at second order with the…

Chaotic Dynamics · Physics 2012-07-25 W. D. McComb , K. Kiyani

Velocity increments over a distance r and turbulent energy dissipation on a box of size r are well described by the multifractal models of fully developed turbulence. These quantities and models however, do not involve time-correlations and…

chao-dyn · Physics 2008-02-03 R. Lima , R. Vilela Mendes

A review of theoretical results on cosmic ray first-order Fermi acceleration at relativistic shock waves is presented, with recent results substantially changing the existing knowledge on these processes. In particular one can not expect…

Astrophysics · Physics 2011-11-10 M. Ostrowski

This article introduces a novel construction of the two-dimensional fractional Brownian motion (2D fBm) with dependent components. Unlike similar models discussed in the literature, our approach uniquely accommodates the full range of model…

We consider particle acceleration by large-scale incompressible turbulence with a lengthscale larger than the particle mean free path. We derive an ensemble-averaged transport equation of energetic charged particles from an extended…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Yutaka Ohira

We introduce a class of stochastic advection problems amenable to analysis of turbulent transport. The statistics of the flow field are represented as a continuous time Markov process, a choice that captures the intuitive notion of…

Fluid Dynamics · Physics 2022-12-01 Andre N. Souza , Tyler Lutz , Glenn R. Flierl

We apply recent advances in quantum gravity to the problem of turbulence. Adopting the AdS/CFT approach we propose a string theory of turbulence that explains the Kolmogorov scaling in 3+1 dimensions and the Kraichnan and Kolmogorov…

General Relativity and Quantum Cosmology · Physics 2011-01-17 Vishnu Jejjala , Djordje Minic , Y. Jack Ng , Chia-Hsiung Tze

We propose a new quantum transition-state theory for calculating Fermi's golden-rule rates in complex multidimensional systems. This method is able to account for the nuclear quantum effects of delocalization, zero-point energy and…

Chemical Physics · Physics 2019-03-27 Manish J. Thapa , Wei Fang , Jeremy O. Richardson

We express the transport coefficients appearing in the second-order evolution equations for bulk viscous pressure and shear stress tensor using Bose-Einstein, Boltzmann, and Fermi-Dirac statistics for the equilibrium distribution function…

Turbulence is an ubiquitous phenomenon in natural and industrial flows. Since the celebrated work of Kolmogorov in 1941, understanding the statistical properties of fully developed turbulence has remained a major quest. In particular,…

Fluid Dynamics · Physics 2017-03-09 Léonie Canet , Vincent Rossetto , Nicolás Wschebor , Guillaume Balarac

We derive the equations of second order dissipative fluid dynamics from the relativistic Boltzmann equation following the method of W. Israel and J. M. Stewart. We present a frame independent calculation of all first- and second-order terms…

Nuclear Theory · Physics 2011-10-03 B. Betz , G. S. Denicol , T. Koide , E. Molnar , H. Niemi , D. H. Rischke

Analytical solutions to the time-dependent Schrodinger equation describing a driven two-level system are invaluable to many areas of physics, but they are also extremely rare. Here, we present a simple algorithm that generates an unlimited…

Quantum Physics · Physics 2012-08-08 Edwin Barnes , S. Das Sarma

In this article, we consider the stochastic wave and heat equations driven by a Gaussian noise which is spatially homogeneous and behaves in time like a fractional Brownian motion with Hurst index $H>1/2$. The solutions of these equations…

Probability · Mathematics 2016-03-31 Raluca M. Balan , Daniel Conus

We derive analytic solutions for the full time dependence of space-fractional Fokker-Planck equations corresponding to stochastic Langevin equations with additive tempered-stable L\'{e}vy noise terms. The drift terms are generalised to be…

Statistical Mechanics · Physics 2021-05-05 Mathew Zuparic , Alexander Kalloniatis

This paper is devoted to a statistical analysis of the fluctuations of velocity and acceleration produced by a random distribution of point vortices in two-dimensional turbulence. We show that the velocity probability density function…

Statistical Mechanics · Physics 2009-10-31 Pierre-Henri Chavanis , Clément Sire

Starting from a Langevin description of active particles that move with constant speed in infinite two-dimensional space and its corresponding Fokker-Planck equation, we develop a systematic method that allows us to obtain the…

Statistical Mechanics · Physics 2014-05-06 Francisco J. Sevilla , Luis A. Gomez Nava

We establish a classification scheme for stochastic acceleration models involving low-frequency plasma turbulence in a strongly magnetized plasma. This classification takes into account both the properties of the accelerating…

Solar and Stellar Astrophysics · Physics 2015-06-05 Nicolas Bian , A. Gordon Emslie , Eduard P. Kontar