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Related papers: Lorentzian Entropies and Olbert's $\kappa$-distrib…

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The notion of group entropy is proposed. It enables to unify and generalize many different definitions of entropy known in the literature, as those of Boltzmann-Gibbs, Tsallis, Abe and Kaniadakis. Other new entropic functionals are…

Statistical Mechanics · Physics 2015-05-28 Piergiulio Tempesta

The kappa distribution of velocities appears routinely in the study of collisionless plasmas present in Earth's magnetosphere, the solar wind among other contexts where particles are unable to reach thermal equilibrium. Originally justified…

Statistical Mechanics · Physics 2025-10-28 Sergio Davis , Biswajit Bora , Cristian Pavez , Leopoldo Soto

Entropy can signify different things: For instance, heat transfer in thermodynamics or a measure of information in data analysis. Many entropies have been introduced and it can be difficult to ascertain their different importance and…

Mathematical Physics · Physics 2025-07-10 Henrik Jeldtoft Jensen , Piergiulio Tempesta

During the past dozen years there have been numerous articles on a relation between entropy and probability which is non-additive and has a parameter $q$ that depends on the nature of the thermodynamic system under consideration. For $q=1$…

Statistical Mechanics · Physics 2009-11-07 Michael Nauenberg

In a previous paper, we introduced an axiomatic system for information thermodynamics, deriving an entropy function that includes both thermodynamic and information components. From this function we derived an entropic probability…

Quantum Physics · Physics 2024-12-18 Benjamin Schumacher , Michael D. Westmoreland

The standard (non-relativistic) $\kappa$-distribution is widely used to fit data and to describe macroscopic thermodynamical behavior, e.g.\ the pressure (temperature) as the second moment of the distribution function. By contrast to a…

Plasma Physics · Physics 2019-09-04 Klaus Scherer , Horst Fichtner , Hans-Jörg Fahr , Marian Lazar

Certain thermal non-equilibrium situations, outside of the astrophysical realm, suggest that entropy production extrema, instead of entropy extrema, are related to stationary states. In an effort to better understand the evolution of…

Astrophysics of Galaxies · Physics 2015-05-27 Eric I. Barnes , Liliya L. R. Williams

Kappa distributions are widely used in space plasma physics to model velocity distribution functions with heavy tails. Parameter estimation in these distributions is, however, complicated by the fact that the kappa distribution does not…

Methodology · Statistics 2026-05-25 Leonardo Herrera-Fuenzalida , Sergio Davis

Classical-like formulas are given in order to evaluate thermal averages of observables belonging to a quantum nonlinear system with dissipation described by the Caldeira-Leggett model [Phys. Rev. Lett. 46, 211 (1981); Ann. Phys. (N.Y.) 149,…

Statistical Mechanics · Physics 2009-10-30 Alessandro Cuccoli , Andrea Rossi , Valerio Tognetti , Ruggero Vaia

For collisionless (or collision-poor) plasma populations which are well described by the $\kappa$-distribution functions (also known as the Kappa or Lorentzian power-laws) a macroscopic interpretation has remained largely questionable,…

Computational Physics · Physics 2019-08-07 Klaus Scherer , Marian Lazar , Edin Husidic , Horst Fichtner

Long-range quantum systems, in which the interactions decay as $1/r^{\alpha}$, are of increasing interest due to the variety of experimental set-ups in which they naturally appear. Motivated by this, we study fundamental properties of…

Quantum Physics · Physics 2026-01-08 Jorge Sánchez-Segovia , Jan T. Schneider , Álvaro M. Alhambra

The generally accepted representation of $\kappa$-distributions in space plasma physics allows for two different alternatives, namely assuming either the temperature or the thermal velocity to be $\kappa$-independent. The present paper aims…

Solar and Stellar Astrophysics · Physics 2016-04-13 M. Lazar , H. Fichtner , P. H. Yoon

The departure of particle distributions from the Maxwellian is commonly observed in space plasmas. These non-Maxwellian distributions which are typical for plasmas that are not in thermal equilibrium, can be modeled with…

Plasma Physics · Physics 2021-09-16 Bojan Arbutina , Vladimir Zekovic

We generalize the usual exponential Boltzmann factor to any reasonable and potentially observable distribution function, $B(E)$. By defining generalized logarithms $\Lambda$ as inverses of these distribution functions, we are led to a…

Statistical Mechanics · Physics 2007-05-23 Rudolf Hanel , Stefan Thurner

Systems with a long-term stationary state that possess as a spatio-temporally fluctuation quantity $\beta$ can be described by a superposition of several statistics, a "super statistics". We consider first, the Gamma, log-normal and…

Statistical Mechanics · Physics 2015-06-05 O. Obregón , A. Gil-Villegas

A non-relativistic Fokker-Planck equation for the electron distribution function is formulated incorporating the effects of stochastic acceleration by whistler-mode waves and Coulomb collisions. The stationary solution $f$ to the equation,…

Plasma Physics · Physics 2015-06-26 Chun-yu Ma , Danny Summers

The apparent thermalization of the particles produced in hadronic collisions can be obtained by quantum entanglement of the partons of the initial state once a fast hard collision is produced. The scale of the hard collision is related to…

High Energy Physics - Phenomenology · Physics 2018-09-13 X. Feal , C. Pajares , R. A. Vazquez

Possible entropy constraints on particle acceleration spectra are discussed. Solar flare models invoke a variety of initial distributions of the primary energy release over the particles of the flare plasma -- ie., the partition of the…

Astrophysics · Physics 2011-05-23 John C Brown , Gregory Beekman , Norman Gray , Alexander L MacKinnon

The recently developed concept of "entropic defect" is important for understanding the foundations of thermodynamics in space plasma physics, and more generally, for systems with physical correlations among their particles. Using this…

Plasma Physics · Physics 2022-11-30 George Livadiotis , David J. McComas

We study the entropy production in non-equilibrium quantum systems without dissipation, which is generated exclusively by the spontaneous breaking of time-reversal invariance. Systems which preserve the total energy and particle number and…

Statistical Mechanics · Physics 2020-03-26 Mihail Mintchev , Paul Sorba