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In this paper, we consider a universe dominated by the extended Chaplygin gas which recently proposed as the last version of Chaplygin gas models. Here, we only consider the second order term which recovers quadratic barotropic fluid…

General Relativity and Quantum Cosmology · Physics 2015-04-01 E. O. Kahya , B. Pourhassan

In this work, we study an inflationary scenario in the presence of Generalized Chaplygin Gas (GCG). We show that in Einstein gravity, GCG is not a suitable candidate for inflation; but in a five dimensional brane world scenario, it can work…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-22 Bikash R Dinda , Sumit Kumar , Anjan A. Sen

In this paper, we study interacting extended Chaplygin gas as dark matter and quintessence scalar field as dark energy with an effective $\Lambda$-term in Lyra manifold. As we know Chaplygin gas behaves as dark matter at the early universe…

General Relativity and Quantum Cosmology · Physics 2016-01-20 H. Saadat

Recent observations from type Ia Supernovae and from cosmic microwave background (CMB) anisotropies have revealed that most of the matter of the Universe interacts in a repulsive manner, composing the so-called dark energy constituent of…

General Relativity and Quantum Cosmology · Physics 2009-11-11 M. S. Santos , S. V. B. Gonçalves , J. C. Fabris , E. M. de Gouveia Dal Pino

Cosmic inflation is arguably the most favoured paradigm of the very early Universe. It postulates an early phase of fast, nearly exponential, and accelerated expansion. Inflationary models are capable of explaining the overall flatness and…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-08 Cristian Joana

This thesis is dedicated to analysing the generation and destruction of quantum correlations in the context of inflationary cosmology and an experiment of 'analogue' preheating. Inflation is a phase of accelerated expansion of the Universe,…

General Relativity and Quantum Cosmology · Physics 2024-12-04 Amaury Micheli

Model independent arguments following from the Covariant Entropy Principle imply that causal diamonds in the very early universe were entirely filled with a single equilibrated system with finite entropy. A universe where this condition…

High Energy Physics - Theory · Physics 2021-09-14 Tom Banks , Willy Fischler

Despite our present-day inability to predict the topology of the universe one may expect that we should be able to detect it in the near future, given the increasing accuracy in the astro-cosmological observations. Motivated by this, we…

Astrophysics · Physics 2007-05-23 M. Makler , B. Mota , M. J. Reboucas

Observational cosmology is in its "golden age" with a vast amount of recent data on the distribution of matter and light in the universe. This data can be used to probe theories of the very early universe. It is small amplitude cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Robert H. Brandenberger

We consider quantum decoherence and entropy increase in early universe cosmology. We first study decoherence in a discrete bipartite quantum system for which a single qubit gets entangled with an environment and the entropy increase is…

High Energy Physics - Theory · Physics 2025-11-06 Sebastian Cespedes , Senarath de Alwis , Fernando Quevedo

In the current framework of Einstein's equations in general relativity (GR), gravity is described by the spacetime curvature. However, there are other descriptions where the origin of gravity can be understood through torsion and…

General Relativity and Quantum Cosmology · Physics 2022-12-02 Nakul Aggarwal , Ali Pourmand , Fatimah Shojai , Harish Parthasarathy

In the standard model of cosmology, the Universe began its expansion with an anomalously low entropy, which then grew dramatically to much larger values consistent with the physical conditions at decoupling, roughly 380,000 years after the…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-22 Fulvio Melia

We investigate properties of the conserved charge in general relativity, recently proposed by one of the present authors with his collaborators, in the inflation era, the matter dominated era and the radiation dominated era of the expanding…

High Energy Physics - Theory · Physics 2023-06-16 Sinya Aoki , Kiyoharu Kawana

We study the cosmological scenario arising from the dynamics of a generalized Chaplygin gas. The equation of state of the system is given in terms of the energy density, $\rho$, and pressure, $p$, by the relationship $p = -…

Astrophysics · Physics 2007-05-23 M. C. Bento , O. Bertolami , A. A. Sen

In this paper, we investigate cosmological consequences of a scenario for recently reported accelerated expansion of the Universe, in which the generalized Chaplygin gas (GCG) along with the baryonic matter are responsible for this observed…

General Relativity and Quantum Cosmology · Physics 2017-05-24 Hamid Shabani

In this work, we investigate the cosmological dynamics of a spatially flat Friedmann--Lema\^itre--Robertson--Walker Universe in the framework of generalized \( \mathcal{F}(\mathcal{R},\Sigma,\mathcal{T}) \) gravity by incorporating…

General Relativity and Quantum Cosmology · Physics 2026-05-15 N. Myrzakulov , S. H. Shekh , Anirudh Pradhan , M. Zeyauddin

The generalized Chaplygin gas (GCG) model in spatially flat universe is investigated. The cosmological consequences led by GCG model including the evolution of EoS parameter, deceleration parameter and dimensionless Hubble parameter are…

General Relativity and Quantum Cosmology · Physics 2011-06-10 M. Malekjani , A. Khodam-Mohammadi , N. Nazari-Pooya

A particular generalization of the Chaplygin inflationary model, using the formalism of Hamilton-Jacobi and elliptic functions, results in a more general non-linear Chaplygin-type equation of state (Chaplygin-Jacobi model). We investigate…

General Relativity and Quantum Cosmology · Physics 2025-03-11 J. A. S. Fortunato , W. S. Hipolito-Ricaldi , N. Videla , J. R. Villanueva

We discuss applications of perturbative quantum gravity in the theory of very early quantum Universe and quantum cosmology. Consistency of the theoretical formalism for quantum effects of matter and correspondence with observational status…

High Energy Physics - Theory · Physics 2023-02-07 Andrei O. Barvinsky , Alexander Yu. Kamenshchik

The modified Chaplygin gas (MCG) cosmological model is derived by using the geometrothermodynamics (GTD) formalism. We show that the MCG corresponds to a system with internal thermodynamic interaction and describes the current accelerated…

General Relativity and Quantum Cosmology · Physics 2019-01-15 Hachemi B. Benaoum , Hernando Quevedo