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The necessary and sufficient conditions for a perfect fluid solution to define a spatially-homogeneous cosmology are achieved. These conditions are Intrinsic, Deductive, Explicit and ALgorithmic, and they offer an IDEAL labeling of these…

General Relativity and Quantum Cosmology · Physics 2024-09-25 Juan Antonio Sáez , Salvador Mengual , Joan Josep Ferrando

In the article it is shown that at presence of fundamental scalar fields determining the masses of the scalar charged particles the global thermodynamic equilibrium (GTE) is compatible with a process of the cosmological expansion of the…

General Physics · Physics 2014-10-10 Yurii Ignat'ev

Static spherically symmetric perfect-fluid solutions of Einstein's equations play a central role in relativistic astrophysics and stellar structure theory. While many exact solutions satisfy Einstein's equations mathematically, only a…

General Relativity and Quantum Cosmology · Physics 2026-05-22 Dina Demissenova , Nurzada Beissen , Kuantay Boshkayev , Hernando Quevedo

The behavior of a decoupled ideal Fermi gas in a homogeneously expanding three-dimensional volume is investigated, starting from an equilibrium spectrum. In case the gas is massless and/or completely degenerate, the spectrum of the gas can…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-16 Andreas Trautner

Thermodynamics of ideal Fermi gas trapped in an external generic power law potential $U=\sum_{i=1} ^d c_i |\frac{x_i}{a_i}|^{n_i}$ are investigated systematically from the grand thermodynamic potential in $d$ dimensional space. These…

Quantum Gases · Physics 2016-04-18 Mir Mehedi Faruk , G. M. Bhuiyan

We use a dynamical systems analysis to investigate the future behaviour of Einstein-Aether cosmological models with a scalar field coupling to the expansion of the aether and a non-interacting perfect fluid. The stability of the equilibrium…

General Relativity and Quantum Cosmology · Physics 2013-03-14 Patrik Sandin , Bassemah Alhulaimi , Alan Coley

Thermodynamics of power means applies to an ideal quantum gas which may be nonextensive. Transition to an ideal classical gas occurs when the empirical temperature exponents of the internal energy and absolute temperature coalesce. Limiting…

Statistical Mechanics · Physics 2007-05-23 B. H. Lavenda

The thermodynamical properties of interacting Bose atoms in a harmonic potential are studied within the mean-field approximation. For weak interactions, the quantum statistics is equivalent to an ideal gas in an effective mean-field…

Quantum Gases · Physics 2015-06-03 Shi-Jie Yang , Yuechan Liu , Shiping Feng

I show that if the total energy of a system of interacting particles may be written as a sum of quasiparticle energies, then the system of quasiparticles can be viewed in general as an ideal gas with fractional exclusion statistics (FES).…

Quantum Gases · Physics 2013-02-12 Dragos-Victor Anghel

In terms of fundamental principles of quantum theory of interacting particles and relativistic kinetic theory there was carried out an analysis of the main principle of standard cosmological scenario - the initial existence of local…

General Relativity and Quantum Cosmology · Physics 2011-06-21 Yurii G. Ignatyev

The explanation of the apparent universality of thermodynamics points toward the extension of the usual conceptual background of the second law. Arguments are collected that a basic guiding idea of stability of thermodynamic equilibrium…

Classical Physics · Physics 2014-07-23 P. Ván

In the paper, the principal aspects of the mathematical theory of equilibrium thermodynamics are distinguished. It is proved that the points of degeneration of a Bose gas of fractal dimension in the momentum space coincide with critical…

General Physics · Physics 2015-06-03 V. P. Maslov

These notes present simple theoretical approaches to study Bose-Einstein condensation in trapped atomic gases and their comparison to recent experimental results : - the ideal Bose gas model - Fermi pseudopotential to model the atomic…

Condensed Matter · Physics 2022-03-23 Yvan Castin

The standard theory of ideal gases ignores the interaction of the gas particles with the thermal radiation (photon gas) that fills the otherwise vacuum space between them. This is an unphysical feature since every material absorbs and…

Classical Physics · Physics 2009-01-14 A. Paglietti

In this work we study the behavior of relativistic ideal Bose and Fermi gases in two space dimensions. Making use of polylogarithm functions we derive a closed and unified expression for their densities. It is shown that both type of gases…

Condensed Matter · Physics 2009-10-31 H. Blas , B. M. Pimentel , J. L. Tomazelli

It is shown that the usual identification of certain averages with the relativistic thermodynamical functions is not possible in the moving reference frame description. The Brownian motion approach is used as the Markovian kinetic…

Condensed Matter · Physics 2016-08-15 Ryszard Zygadło

The question of how classical thermodynamic laws emerge from the underlying quantum substrate lies at the foundations of physics. Here, we examine the validity of the ideal gas law (IGL) for a single quantum particle confined within a…

Quantum Physics · Physics 2025-07-21 Alejandro M. F Rivas , Eduardo G. Vergini , Leonardo Ermann , Gabriel G. Carlo

The pressure of an ideal relativistic Fermi gas is computed as an infinite series for high temperatures at nonzero chemical potentials. The expansion of the particle number density, scalar density, and entropy density as first derivatives…

Mathematical Physics · Physics 2015-11-18 A. S. Khvorostukhin

We develop a formulation of global thermodynamics for equilibrium systems under the influence of gravity. The free energy for simple fluids is extended to include a dependence on $(T, V, N, mgL)$, where $L$ represents the vertical system…

Statistical Mechanics · Physics 2025-06-26 Naoko Nakagawa , Shin-ichi Sasa , Takamichi Hirao , Tsuyoshi Shiina , Kyosuke Tachi , Akira Yoshida

Comparison of the thermodynamic entropy with Boltzmann's principle shows that under conditions of constant volume the total number of arrangements in simple thermodynamic systems with temperature-independent heat capacities is TC/k. A…

General Physics · Physics 2009-11-13 David Sands
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