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The present work is a second in the series of investigation of the background dynamics in brane cosmology when dark energy is coupled to dark matter by a suitable interaction. Here, dark matter is chosen in the form of perfect fluid with…

General Physics · Physics 2019-06-21 Sujay Kr. Biswas , Subenoy Chakraborty

We study the role that tachyon fields may play in cosmology as compared to the well-established use of minimally coupled scalar fields. We first elaborate on a kind of correspondence existing between tachyons and minimally coupled scalar…

High Energy Physics - Theory · Physics 2009-11-10 V. Gorini , A. Yu. Kamenshchik , U. Moschella , V. Pasquier

We construct a scalar field based cosmological model, possessing a cosmological singularity characterized by a finite value of the cosmological radius and an infinite scalar curvature. Using the methods of the qualitative theory of…

General Relativity and Quantum Cosmology · Physics 2009-01-16 Francesco Cannata , Alexander Yu. Kamenshchik , Daniele Regoli

The Universe is currently in a phase of accelerated expansion, a fact that was experimentally proven in the late 1990s. Cosmological models involving scalar fields allow the description of this accelerated expansion regime in the Cosmos and…

General Relativity and Quantum Cosmology · Physics 2023-10-11 Joao R. L. Santos , S. Santos da Costa , Romario S. Santos

Nontopological fermionic solitons exist across a diverse range of particle physics models and have rich cosmological implications. This study establishes a general framework for calculating fermionic soliton profiles under arbitrary scalar…

High Energy Physics - Phenomenology · Physics 2024-08-27 Ke-Pan Xie

We consider a noncommutative standard model with a minimal coupling scalar field and a dynamical deformation between the canonical momenta of its scale factor and scalar field, and a chameleon model with a non-minimally coupling scalar…

General Relativity and Quantum Cosmology · Physics 2018-05-25 Nasim Saba , Mehrdad Farhoudi

We find that the expansion of the universe is accelerating by analyzing the recent observation data of type $\textsc{I}a$ supernova(SN-Ia) .It indicates that the equation of state of the dark energy might be smaller than -1,which leads to…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Zu-Yao Sun , You-Gen Shen

We calculate finite-temperature corrections to the decay rate of a generic neutral (pseudo)scalar particle that decays into (pseudo)scalars or fermion-antifermion pairs. The ratio of the finite-temperature decay rate to the zero-temperature…

High Energy Physics - Phenomenology · Physics 2015-08-06 Chiu Man Ho , Robert J. Scherrer

Concepts of quantum open systems and ideas of correlation dynamics in nonequilibrium statistical mechanics, as well as methods of closed-time-path effective action and influence functional in quantum field theory can be usefully applied for…

General Relativity and Quantum Cosmology · Physics 2007-05-23 B. L. Hu

We present a study of the decay of metastable states of a scalar field via thermal activation, in the presence of a finite density of fermions. The process we consider is the nucleation of ``{\it droplets}'' of true vacuum inside the false…

High Energy Physics - Theory · Physics 2009-10-28 E. S. Fraga , C. A. A. De Carvalho

We propose a scenario of the beginning of inflation in which the non-vacuum value of the scalar field that drives inflation develops dynamically due to the non-minimal coupling to gravity. In this scenario, inflation emerges as an…

High Energy Physics - Phenomenology · Physics 2016-09-06 M. V. Libanov , V. A. Rubakov , P. G. Tinyakov

We show that it is possible to realize an inflationary scenario even without conversion of the false vacuum energy to radiation. Such cosmological models have a deflationary stage in which $Ha^2$ is decreasing and radiation produced by…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Boris Spokoiny

We report on a numerical study of real-time dynamics of electromagnetically interacting chirally imbalanced lattice Dirac fermions within the classical statistical field theory approach. Namely, we perform exact simulations of the real-time…

High Energy Physics - Theory · Physics 2016-07-13 P. V. Buividovich , M. V. Ulybyshev

Simple scalar field cosmological models are considered describing gravity assisted crossing of the phantom divide line. This crossing or (de)-phantomization characterized by the change of the sign of the kinetic term of the scalar field is…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Alexander A. Andrianov , Francesco Cannata , Alexander Y. Kamenshchik

We present and examine a kinetically coupled tachyon dark energy model, where a tachyon scalar field interacts with the matter sector. More specifically, we deduce this cosmological setting from a generalised interacting dark energy model…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Francesco Pace , Alberto Rozas-Fernández , Özgen Tunç Türker

In view of growing interest in long range scalar forces in the early universe to generate primordial black holes, we study in detail the general relativistic formulation of a Fermi gas interacting with a scalar field in cosmology. Our main…

High Energy Physics - Theory · Physics 2021-06-23 Guillem Domènech , Misao Sasaki

We explore the cosmological consequences of having the fluctuations of the inflaton field entangled with those of another scalar, within the context of a toy model consisting of non-interacting, minimally coupled scalars in a fixed de…

High Energy Physics - Theory · Physics 2015-06-22 Andreas Albrecht , Nadia Bolis , R. Holman

The zero temperature effective equation of motion is derived for a scalar field interacting with other fields. For a broad range of cases, involving interaction with as few as one or two fields, dissipative regimes are found for the scalar…

High Energy Physics - Phenomenology · Physics 2009-11-07 Arjun Berera , Rudnei O. Ramos

In this paper, we investigate the role of scalar field potentials in the dynamical evolution of the Universe. A gravity theory with a non-minimally coupled scalar field with torsion in the geometrical action simulating effective dark energy…

General Relativity and Quantum Cosmology · Physics 2024-09-05 B. Mishra , S. A. Kadam , S. K. Tripathy

In this article we study the properties of the flat FRW chameleon cosmology in which the cosmic expansion of the Universe is affected by the chameleon field and dark energy. In particular, we perform a detailed examination of the model in…

General Physics · Physics 2015-06-03 Hossein Farajollahi , Amin Salehi