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In this letter we apply dynamical system methods to study all evolutional paths admissible for all initial conditions of the FRW cosmological model with a non-minimally coupled to gravity scalar field and a barotropic fluid. We choose…

Astrophysics · Physics 2011-07-13 Marek Szydlowski , Orest Hrycyna

We develop a novel framework for describing quantum fluctuations in field theory, with a focus on cosmological applications. Our method uniquely circumvents the use of operator/Hilbert-space formalism, instead relying on a systematic…

General Relativity and Quantum Cosmology · Physics 2024-06-25 Ding Ding , Zhao Yu , Yidun Wan

We explore dynamics of cosmological models with bounce solutions evolving on a spatially flat Friedmann-Lemaitre-Robertson-Walker background. We consider cosmological models that contain the Hilbert-Einstein curvature term, the induced…

General Relativity and Quantum Cosmology · Physics 2016-12-08 Ekaterina O. Pozdeeva , Maria A. Skugoreva , Alexey V. Toporensky , Sergey Yu. Vernov

We investigate the virialization of cosmic structures in the framework of flat FLRW cosmological models, in which the vacuum energy density evolves with time. In particular, our analysis focuses on the study of spherical matter…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 S. Basilakos , M. Plionis , J. Sola

Open FRW model in Loop Quantum Cosmology is under consideration. The left and right invariant vector fields and holonomies along them are studied. It is shown that in the hyperbolic geometry of $k=-1$ it is possible to construct a suitable…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Lukasz Szulc

We study the dynamics of the closed scalar field FRW cosmological models in the framework of the so called Unified Dark Matter (UDM) scenario. Performing a theoretical as well as a numerical analysis we find that there is a strong…

Astrophysics · Physics 2008-12-18 Georgios Lukes-Gerakopoulos , Spyros Basilakos , George Contopoulos

In a new model that we proposed, nonperturbative vacuum contributions to the effective action of a free quantized massive scalar field lead to a cosmological solution in which the scalar curvature becomes constant after a time $t_j$ (when…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Leonard Parker , Alpan Raval

We investigate spatially flat isotropic cosmological models which contain a scalar field with an exponential potential and a perfect fluid with a linear equation of state. We include an interaction term, through which the energy of the…

Astrophysics · Physics 2008-11-26 Andrew P. Billyard , Alan A. Coley

We examine the quantum loop effects on the single-field inflationary models in a spatially flat Friedmann-Robertson-Walker (FRW) cosmological space-time with a general self-interacting scalar field potential, which is modeled in terms of…

General Relativity and Quantum Cosmology · Physics 2020-02-05 Wei-Can Syu , Da-Shin Lee , Kin-Wang Ng

In this work, we use the dynamical system approach to explore the cosmological background evolution of the scalar-tensor representation of $f(R,T)$ gravity, where $R$ is the Ricci scalar and $T$ is the trace of the stress-energy tensor. The…

General Relativity and Quantum Cosmology · Physics 2024-04-04 Tiago B. Gonçalves , João Luís Rosa , Francisco S. N. Lobo

Loop quantum cosmology of the closed isotropic model is studied with a special emphasis on a comparison with traditional results obtained in the Wheeler-DeWitt approach. This includes the relation of the dynamical initial conditions with…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Martin Bojowald , Kevin Vandersloot

We study the dynamics of isotropic and homogeneous universes in the generalized Ho\v{r}ava-Lifshitz gravity, and classify all possible evolutions of vacuum spacetime. In the case without the detailed balance condition, we find a variety of…

High Energy Physics - Theory · Physics 2010-11-16 Kei-ichi Maeda , Yosuke Misonoh , Tsutomu Kobayashi

We consider a time independent Schrodinger type equation derived from the equations of motion that drives a single scalar field in a standard cosmology model for inflation in a flat space-time with a Friedman-Robertson-Walker (FRW) metric…

General Relativity and Quantum Cosmology · Physics 2010-01-05 N. Barbosa-Cendejas , M. A. Reyes

In this paper we study possible observational consequences of the bouncing cosmology. We consider a model where a phase of inflation is preceded by a cosmic bounce. While we consider in this paper only that the bounce is due to loop quantum…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Jakub Mielczarek , Michal Kamionka , Aleksandra Kurek , Marek Szydlowski

In this study, we consider three dark energy models in which $\Lambda$ is not constant, but has a dynamic nature that depends on the Hubble parameter $H$ and/or its time derivative $\dot{H}$. We analyze the generalized running vacuum model,…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-05 Christine R. Farrugia , Joseph Sultana , Jurgen Mifsud

Friedmann-Robertson-Walker cosmological models with a massive scalar field are studied in the presence of hydrodynamical matter in the form of a perfect fluid. The ratio of the number of solutions without inflation to the total number of…

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

In this paper we investigate the asymptotic behavior of the cosmological model based on phantom scalar field on the ground of qualitative analysis of the system of the cosmological model's differential equations and show that as opposed to…

General Relativity and Quantum Cosmology · Physics 2017-04-26 Yu. G. Ignat'ev , A. A. Agathonov

Quantum reduced loop gravity is designed to consistently study symmetry reduced systems within the loop quantum gravity framework. In particular, it bridges the gap between the effective cosmological models of loop quantum cosmology and the…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Emanuele Alesci , Aurélien Barrau , Gioele Botta , Killian Martineau , Gabriele Stagno

The $q$-theory approach to the cosmological constant problem is reconsidered. The new observation is that the effective classical $q$-theory gets modified due to the backreaction of quantum-mechanical particle production by spacetime…

High Energy Physics - Theory · Physics 2016-09-13 F. R. Klinkhamer , G. E. Volovik

We construct the cosmological model to explain the cosmological constant problem. We built the extension of the standard cosmological model $\Lambda$CDM by consideration of decaying vacuum energy represented by the running cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-08 Marek Szydlowski