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Related papers: Microcanonical entropy for classical systems

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Although an intimate relation between entropy and diffusion has been advocated for many years and even seems to have been verified in theory and experiments, a quantitatively reliable study, and any derivation of an algebraic relation…

Statistical Mechanics · Physics 2020-07-22 Subhajit Acharya , Biman Bagchi

A microscopic understanding of the thermodynamic entropy in quantum systems has been a mystery ever since the invention of quantum mechanics. In classical physics, this entropy is believed to be the logarithm of the volume of phase space…

Quantum Physics · Physics 2013-05-08 J. M. Deutsch , Haibin Li , Auditya Sharma

It is shown that the recently introduced singularities of the microcanonical entropy like "microcanonical phase transitions", and exotic pattern of the microcanonical caloric curve T(E) like multi-valuednes or the appearance of "dinosaur's…

Statistical Mechanics · Physics 2007-05-23 D. H. E. Gross

The framework of non-extensive statistical mechanics, proposed by Tsallis, has been used to describe a variety of systems. The non-extensive statistical mechanics is usually introduced in a formal way, using the maximization of entropy. In…

Statistical Mechanics · Physics 2016-02-17 Julius Ruseckas

The fundamental assumption of statistical mechanics is that the system is equally likely in any of the accessible microstates. Based on this assumption, the Boltzmann distribution is derived and the full theory of statistical thermodynamics…

Quantum Physics · Physics 2015-05-18 X. L. Huang , B. Cui , X. X. Yi

We propose a new approach to justify the use of the microcanonical ensemble for isolated macroscopic quantum systems. Since there are huge number of independent observables in a macroscopic system, we cannot see all of them. Actually what…

Statistical Mechanics · Physics 2008-02-25 Ayumu Sugita

We develop a geometric theory of phase transitions (PTs) for Hamiltonian systems in the microcanonical ensemble. This theory allows to reformulate Bachmann's classification of PTs for finite-size systems in terms of geometric properties of…

Statistical Mechanics · Physics 2022-06-29 Loris Di Cairano

We demonstrate that the Gibbs-Shannon entropy is applicable to non-equilibrium systems of any size and boundary conditions. The change in microscopic entropy can be attributed to the stochastic nature of dynamic processes and to the…

Statistical Mechanics · Physics 2020-10-13 Jianzhong Wu

Prompted by the realisation that the statistical entropy of an ideal gas in the micro-canonical ensemble should not fluctuate or change over time, the meaning of the H-theorem is re-interpreted from the perspective of information theory in…

General Physics · Physics 2013-01-09 David Sands , Jeremy Dunning-Davies

The metriplectic formalism is useful for describing complete dynamical systems which conserve energy and produce entropy. This creates challenges for model reduction, as the elimination of high-frequency information will generally not…

Numerical Analysis · Mathematics 2022-12-28 Anthony Gruber , Max Gunzburger , Lili Ju , Zhu Wang

We compare phase transition(-like) phenomena in small model systems for both microcanonical and canonical ensembles. The model systems correspond to a few classical (non-quantum) point particles confined in a one-dimensional box and…

Statistical Mechanics · Physics 2007-05-23 Jörn Dunkel , Stefan Hilbert

The quest for a microscopic foundation of Thermodynamics is addressed within the Nonunitary Newtonian Gravity model through the study of a specific closed system, namely a three-dimensional harmonic nanocrystal. A numerical calculation of…

Statistical Mechanics · Physics 2020-03-12 Sergio De Filippo , Filippo Maimone , Adele Naddeo , Giovanni Scelza

Statistical formulations of thermodynamic entropy, such as those by Boltzmann and Gibbs, were originally developed for classical systems and are well understood in that context. However, the foundational aspects of quantum statistical…

Quantum Physics · Physics 2025-10-08 Smitarani Mishra , Shaon Sahoo

It is generally believed that, in the thermodynamic limit, the microcanonical description as a function of energy coincides with the canonical description as a function of temperature. However, various examples of systems for which the…

Statistical Mechanics · Physics 2016-01-13 Tiziano Squartini , Joey de Mol , Frank den Hollander , Diego Garlaschelli

We develop new modified cosmological scenarios by applying the first law of thermodynamics at the Universe horizon, utilizing a new entropic functional that generalizes the standard Boltzmann-Gibbs-Shannon entropy. In particular, starting…

General Relativity and Quantum Cosmology · Physics 2026-02-24 G. G. Luciano , E. N. Saridakis

We show that the canonical finite size scaling of the specific heat emerges naturally - and in some sense trivially - from the assumption that the microcanonical specific entropy exhibits no substantial system size dependence.

Statistical Mechanics · Physics 2007-05-23 M. Promberger

The microscopic derivation of the second law for macroscopic system is given under the phenomenological assumption that both the initial and final states are described by mutually different canonical ensembles. In particular, it is also…

Classical Physics · Physics 2011-11-08 Takaaki Monnai

We show that entropy is globally concave with respect to energy for a rich class of mean field interactions, including regularizations of the the point-vortex model in the plane, plasmas and self-gravitating matter in 2D, as well as the…

Mathematical Physics · Physics 2022-11-30 Robert J. Berman

A diagonal entropy, which depends only on the diagonal elements of the system's density matrix in the energy representation, has been recently introduced as the proper definition of thermodynamic entropy in out-of-equilibrium quantum…

Statistical Mechanics · Physics 2012-02-17 Lea F. Santos , Anatoli Polkovnikov , Marcos Rigol

The paper demonstrates that the canonical probability distribution of the occupancy numbers of a bosonic system is multinomial, and shows how the thermodynamics of the canonical system descends from this distribution. The categorical…

Statistical Mechanics · Physics 2025-11-25 Arnaldo Spalvieri