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The possibility of an emergent universe solution to Einstein's field equations allowing for an irreversible creation of matter at the expense of the gravitational field is shown. With the universe being chosen as spatially flat FRW…

General Relativity and Quantum Cosmology · Physics 2016-09-27 Sunandan Gangopadhyay , Anirban Saha , S. Mukherjee

The paper deals with generalized Rastall theory of gravity and its cosmological consequences in the background of homogeneous and isotropic flat FLRW model with perfect fluid as the matter context. The model shows a non singular era…

General Relativity and Quantum Cosmology · Physics 2018-10-29 Dipanjana Das , Sourav Dutta , Subenoy Chakraborty

In this paper we have given a generalisation of the earlier work by Prigogine et al. who have constructed a phenomenological model of entropy production via particle creation in the very early universe generated out of the vacuum rather…

General Relativity and Quantum Cosmology · Physics 2015-06-05 G. K. Goswami , Mandwi Trivedi

Observations of the cosmic microwave sky are revealing the primordial non-uniformities from which all structure in the Universe grew. The only known physical mechanism for generating the inhomogeneities we see involves the amplification of…

Astrophysics · Physics 2009-10-31 Neil Turok

We explore the derivation of the Friedmann equations from a thermodynamic perspective, applying the unified first law of thermodynamics to the apparent horizon of a flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe. We extend this…

General Relativity and Quantum Cosmology · Physics 2026-01-29 Víctor H. Cárdenas , Miguel Cruz , Samuel Lepe

In this paper, we consider a nonminimal coupling model between gravity and nonlinear electrodynamics with cosmological constant. This cosmological model is designed to account for both the inflationary epoch of the early universe and the…

General Relativity and Quantum Cosmology · Physics 2024-10-10 Chilwatun Nasiroh , Ramy F. Izzah , Fiki T. Akbar , Bobby E. Gunara

A model for the Universe is proposed where it is considered as a mixture of scalar and matter fields. The particle production is due to an irreversible transfer of energy from the gravitational field to the matter field and represented by a…

General Relativity and Quantum Cosmology · Physics 2017-08-23 G. M. Kremer , M. C. N. Teixeira da Silva

We explore the cosmological implications at effective level of matter creation effects in a dissipative fluid for a FLRW geometry; we also perform a statistical analysis for this kind of model. By considering an inhomogeneous Ansatz for the…

General Relativity and Quantum Cosmology · Physics 2021-01-01 Víctor H. Cárdenas , Miguel Cruz , Samuel Lepe

We investigate the matter creation processes during the reheating period at the end of inflation in the early Universe, by using the irreversible thermodynamic of open systems. The matter content of the Universe is assumed to consist of the…

General Relativity and Quantum Cosmology · Physics 2018-10-09 Juntong Su , Tiberiu Harko , Shi-Dong Liang

In `entropic cosmology', instead of a cosmological constant $\Lambda$, an extra driving term is added to the Friedmann equation and the acceleration equation, taking into account the entropy and the temperature on the horizon of the…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-14 Nobuyoshi Komatsu , Shigeo Kimura

Entropic-force cosmology provides, in contrast with dark energy descriptions, a concrete physical understanding of the accelerated expansion of the universe. The acceleration appears to be a consequence of the entropy associated with the…

General Relativity and Quantum Cosmology · Physics 2022-08-15 D. J. Zamora , C. Tsallis

In a homogeneous and isotropic universe with non-zero spatial curvature we consider the effects of gravitational particle production in the dynamics of the universe. We show that the dynamics of the universe in such a background is…

General Relativity and Quantum Cosmology · Physics 2017-05-31 Andronikos Paliathanasis , John D. Barrow , Supriya Pan

We present a novel extended version of the $\Lambda$CDM model that provides analytical solution for Hubble parameter uniting all epochs of cosmic evolution starting from inflation to late-acceleration, with intermediate radiation and…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-31 Vishnu A Pai , Titus K Mathew

In a unified picture both inflation and present dynamical dark energy arise from the same scalar field. The history of the Universe describes a crossover from a scale invariant "past fixed point" where all particles are massless, to a…

High Energy Physics - Theory · Physics 2015-12-09 C. Wetterich

Introducing an effective refraction index of an isotropic cosmic medium, we investigate the cosmological fluid dynamics which is consistent with a conformal, timelike symmetry of a corresponding ``optical'' metric. We demonstrate that this…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Winfried Zimdahl , Alexander B. Balakin

The work deals with the thermodynamical aspects of the cosmic substratum which is dissipative in nature. For homogeneous and isotropic model of the Universe this dissipative phenomenon is effective bulk viscous pressure in nature and is…

General Relativity and Quantum Cosmology · Physics 2018-06-04 Pritikana Bhandari , Sourav Haldar , Subenoy Chakraborty

Inflation has been the leading early universe scenario for two decades, and has become an accepted element of the successful `cosmic concordance' model. However, there are many puzzling features of the resulting theory. It requires both…

High Energy Physics - Theory · Physics 2009-11-10 Neil Turok , Paul J. Seinhardt

A relativistic kinetic description for the irreversible thermodynamic process of gravitationally induced particle production is proposed in the context of an expanding Friedmann-Robertson-Walker (FRW) geometry. We show that the covariant…

General Relativity and Quantum Cosmology · Physics 2014-11-25 J. A. S. Lima , I. P. Baranov

A new cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation…

General Relativity and Quantum Cosmology · Physics 2015-06-22 J. A. S. Lima , L. L. Graef , D. Pavón , S. Basilakos

Cosmological evolution driven incorporating continuous particle creation by the time-varying gravitational field is investigated. We consider a spatially flat, homogeneous and isotropic universe with two matter fluids in the context of…

General Relativity and Quantum Cosmology · Physics 2019-02-20 Supriya Pan , John D. Barrow , Andronikos Paliathanasis