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We consider minimal extensions of the recently proposed Mimetic Dark Matter and show that by introducing a potential for the mimetic non-dynamical scalar field we can mimic nearly any gravitational properties of the normal matter. In…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-31 Ali H. Chamseddine , Viatcheslav Mukhanov , Alexander Vikman

The thermodynamic interpretation of the Stephani Universes is studied in detail. The general expression of the speed of sound and of the thermodynamic schemes associated with a thermodynamic solution is obtained. The constraints imposed on…

General Relativity and Quantum Cosmology · Physics 2024-09-04 Salvador Mengual , Joan Josep Ferrando , Juan Antonio Sáez

A cosmological model based on holographic scenarios is formulated in a flat Friedmann-Robertson-Walker universe. To formulate this model, the cosmological horizon is assumed to have a general entropy and a general temperature (including…

General Relativity and Quantum Cosmology · Physics 2024-01-09 Nobuyoshi Komatsu

We perform a comprehensive thermodynamic analysis of three sign-switching dark energy models in a flat FLRW cosmology: graduated dark energy (gDE), sign-switching cosmological constant ($\Lambda_s$), and smoothed sign-switching cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-24 David Tamayo

We investigate cosmological density perturbations in a covariant and gauge-invariant formalism, incorporating relativistic causal thermodynamics to give a self-consistent description. The gradient of density inhomogeneities splits…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Roy Maartens , Josep Triginer

Temperature effects in a scalar field non-minimally coupled to gravity are investigated. The Thermo Field Dynamics formalism is used. This is a topological field theory that allows us to calculate different effects, such as the…

General Relativity and Quantum Cosmology · Physics 2022-03-22 A. F. Santos , Faqir C. Khanna

In this paper we show how almost cosymplectic structures are a natural framework to study thermodynamical systems. Indeed, we are able to obtain the same evolution equations obtained previously by Gay-Balmaz and Yoshimura (see Entropy,…

Mathematical Physics · Physics 2024-12-25 Manuel de León , Jaime Bajo

The effective field theory of cosmological perturbations stems from considering a cosmological background solution as a state displaying spontaneous breaking of time translations and (adiabatic) perturbations as the related Nambu-Goldstone…

High Energy Physics - Theory · Physics 2015-06-16 Federico Piazza , Filippo Vernizzi

Assuming a classical statistical system of point particles the fundamental equations of continuum thermomechanics (continuity equation, equation of motion, and energy equation) shall be derived exactly. The macroscopic state functions…

Statistical Mechanics · Physics 2010-06-03 Walter Noll

We present a Mathematica package for performing algebraic and numerical computations in cosmological models based on supersymmetric theories. The programs allow for (I) evaluation and study of the properties of a scalar potential in a large…

High Energy Physics - Theory · Physics 2007-05-23 Renata Kallosh , Sergey Prokushkin

In this review we focus on the main cosmological implications of the Group Field Theory approach, according to which an effective continuum macroscopic dynamics can be extracted from the underlying formalism for quantum gravity. Within this…

General Relativity and Quantum Cosmology · Physics 2022-04-27 Luciano Gabbanelli , Silvia De Bianchi

Problem of cosmological singularity is discussed in the framework of gauge theories of gravitation. Generalizing cosmological Friedmann equations (GCFE) for homogeneous isotropic models including scalar fields and usual gravitating matter…

General Relativity and Quantum Cosmology · Physics 2007-05-23 A. V. Minkevich

The large-scale structure of the Universe is well approximated by the Friedmann equations, parametrized by several energy densities which can be observationally inferred. A natural question to ask is: How different would the Universe be if…

General Relativity and Quantum Cosmology · Physics 2025-01-20 Arthur G. Suvorov

Phantom cosmology allows to account for dynamics and matter content of the universe tracing back the evolution to the inflationary epoch, considering the transition to the non-phantom standard cosmology (radiation/matter dominated eras) and…

High Energy Physics - Theory · Physics 2008-11-26 S. Capozziello , S. Nojiri , S. D. Odintsov

The paper uses geometrical arguments to derive equations with relevance for cosmology; 5-dimensional spacetime is assumed because it has been shown in other works to provide a setting for significant unification of different areas of…

General Physics · Physics 2008-01-29 Jose B. Almeida

Dark matter and dark energy are essential in the description of the late Universe, since at least the epoch of equality. On the other hand, the inflation is also necessary and demands a "dark" component, usually associated to a scalar field…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-08 Jorge L. Cervantes-Cota , Alejandro Aviles , Josue De-Santiago

We investigate the creation of dark matter particles as a result of the decay of the scalar field in the framework of warm inflationary models, by using the irreversible thermodynamics of open systems with matter creation/annihilation. We…

General Relativity and Quantum Cosmology · Physics 2023-03-07 Teodora Matei , Tiberiu Harko , Gabriela Mocanu

Cosmological correlation functions are central observables in modern cosmology, as they encode properties of the early universe. In this paper, we derive novel canonical differential equations for wavefunction coefficients in power-law FRW…

High Energy Physics - Theory · Physics 2025-12-02 Mattia Capuano , Livia Ferro , Tomasz Lukowski , Alessandro Palazio

We investigate the validity of the generalized second law of thermodynamics, in the cosmological scenario where dark energy interacts with both dark matter and radiation. Calculating separately the entropy variation for each fluid component…

High Energy Physics - Theory · Physics 2010-07-20 Mubasher Jamil , Emmanuel N. Saridakis , M. R. Setare

The cosmographic technique is a powerful model-independent tool for distinguishing between competing cosmological scenarios. The key strengths and weaknesses of standard cosmography are discussed in view of healing the convergence problem…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-01 Salvatore Capozziello , Rocco D'Agostino