English
Related papers

Related papers: Anisotropic $k$-essence

200 papers

The dynamics of the tilted axisymmetric Bianchi IX cosmological models are explored allowing energy flux in the source fluid. The Einstein equations and the continuity equation are presented treating the equation of state $w$ and the tilt…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-30 Peter Sundell , Tomi Koivisto

We consider a mimetic set up in which the mimetic scalar is coupled to a vector field. It is shown that such a field with a time-like component does not contribute to the background equations and yet produces healthy isocurvature…

General Relativity and Quantum Cosmology · Physics 2018-06-20 M. H. Abbassi , A. Jozani , H. R. Sepangi

The present study deals with spatially homogeneous and anisotropic locally rotationally symmetric (LRS) Bianchi type I cosmological model with dominance of dark energy. To get the deterministic model of Universe, we assume that the shear…

General Physics · Physics 2012-01-24 Anil Kumar Yadav , Bijan Saha

In this paper, we will deepen the understanding of some fluid models proposed by other authors for the description of dark energy. Specifically, we will show that the so-called (Modified) Berthelot fluid is the hydrodynamic realization of…

General Relativity and Quantum Cosmology · Physics 2023-01-31 Muhsin Aljaf , Daniele Gregoris , Martiros Khurshudyan

We investigate the possibility of replacing the cosmological constant with gradual condensation of a scalar field produced during the decay of a superheavy dark matter. The advantage of this class of models to the ordinary quintessence is…

Astrophysics · Physics 2009-11-10 Houri Ziaeepour

Disformal transformations have proven to be very useful to devise models of the dark sector. In the present paper we apply such transformation to a single scalar field theory as a way to drive the field into a slow roll phase. The canonical…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-04 M. Zumalacarregui , T. S. Koivisto , D. F. Mota , P. Ruiz-Lapuente

We propose a dark energy model where a scalar field $\phi$ has nonlinear self-interactions in the presence of a dilatonic coupling with the Ricci scalar. This belongs to a sub-class of theories beyond Horndeski, which accommodates covariant…

General Relativity and Quantum Cosmology · Physics 2016-01-11 Ryotaro Kase , Shinji Tsujikawa , Antonio De Felice

Anisotropic dark energy cosmological models are constructed in the frame work of generalised Brans-Dicke theory with a self interacting potential. Wet dark fluid characterized by a linear equation of state is considered as the source of…

General Physics · Physics 2017-05-10 Sunil K. Tripathy , Dipanjali Behera , Bivudutta Mishra

We consider a model where both dark energy and dark matter originate from the coupling of a scalar field with a non-conventional kinetic term to, both, a metric measure and a non-metric measure. An interacting dark energy/dark matter…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Stefano Ansoldi , Eduardo I. Guendelman

We investigate the quantum modified cosmological dynamical equations in a Friedmann-Robertson-Walker universe filled with a barotropic fluid and a general non-canonical scalar field characterized by a Lagrangian similar to k-essence model…

General Relativity and Quantum Cosmology · Physics 2024-03-06 Rituparna Mandal , Soma Sanyal

We constrain the parameters of dynamical dark energy in the form of a classical scalar field with barotropic equation of state jointly with other cosmological parameters using various combined datasets including the CMB power spectra from…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Olga Sergijenko , Bohdan Novosyadlyj

The Maxwell action is conformally invariant and classically ignorant of conformally flat metrics. However, if the vector lives in a disformal metric--- as it does if residing upon a moving brane---this is no longer true. The disformal…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Tomi S. Koivisto , Federico R. Urban

The paper deals with Bianchi type V Universe, which has dynamical energy density. We consider Bianchi type V space-time, introducing three different skewness parameters along spatial directions to quantify the deviation of pressure from…

General Physics · Physics 2015-03-17 Anil Kumar Yadav

In the present article authors investigate the anisotropic stellar solutions admitting Finch-Skea symmetry (viable and non-singular metric potentials) in the presence of some exotic matter fields, such as: Bose-Einstein Condensate (BEC)…

General Relativity and Quantum Cosmology · Physics 2022-11-04 Oleksii Sokoliuk , Alexander Baransky , P. K. Sahoo

We numerically and analytically explore the background cosmological dynamics of multifield dark energy with highly nongeodesic or "spinning" field-space trajectories. These extensions of standard single-field quintessence possess appealing…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-25 Johannes R. Eskilt , Yashar Akrami , Adam R. Solomon , Valeri Vardanyan

We consider a model of dark energy/matter unification based on a k-essence type of theory similar to tachyon condensate models. Using an extension of the general relativistic spherical model which incorporates the effects of both pressure…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Neven Bilic , Gary B. Tupper , Raoul D. Viollier

In our study, we explored the properties of a spatially homogeneous and anisotropic Bianchi type V I0 Universe. Our investigation centered on integrating cosmic domain walls into the f(R, T) theory of gravitation, initially proposed by…

General Relativity and Quantum Cosmology · Physics 2024-03-05 V. R. Patil , J. L. Pawde , R. V. Mapari , S. K. Waghmare

Models with vector fields acquiring a non-vanishing vacuum expectation value along one spatial direction have been proposed to sustain a prolonged stage of anisotropic accelerated expansion. Such models have been used for realizations of…

Astrophysics · Physics 2009-04-08 Burak Himmetoglu , Carlo R. Contaldi , Marco Peloso

In this paper we investigate, from the dynamical systems perspective, the evolution of an scalar field with arbitrary potential trapped in a Randall-Sundrum's Braneworld of type 2. We consider an homogeneous but anisotropic Bianchi I (BI)…

General Relativity and Quantum Cosmology · Physics 2012-10-29 Dagoberto Escobar , Carlos R. Fadragas , Genly Leon , Yoelsy Leyva

This paper is devoted to study Bianchi type I cosmological model in Brans-Dicke theory with self-interacting potential by using perfect, anisotropic and magnetized anisotropic fluids. We assume that the expansion scalar is proportional to…

General Relativity and Quantum Cosmology · Physics 2015-06-04 M. Sharif , Saira Waheed