scholarly journals Interaction between Dark Matter and Dark Energy and the Cosmological Coincidence Problem

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Kourosh Nozari ◽  
Noushin Behrouz ◽  
Narges Rashidi
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Exponential Potential ◽  
Complex Velocity ◽  
Dark Sector ◽  
Coincidence Problem ◽  
Theories Of Gravity ◽  
The Stability ◽  
Quintessence Model

We consider a quintessence model of dark energy inspired by scalar-tensor theories of gravity where the scalar field is nonminimally coupled to gravity and dark matter. By considering exponential potential as self-interaction potential, the stability and existence of the critical points are discussed in details. With nonminimally coupled dark sector with gravity, we obtain scaling solutions to address the coincidence problem by considering complex velocity for dark matter. The statefinder diagnostic shows that the equation of state reachesΛCDMmodel in the future.

scholarly journals Interacting Dark Matter andq-Deformed Dark Energy Nonminimally Coupled to Gravity

2016 ◽  
Vol 2016 ◽  
pp. 1-17
Author(s):  
Emre Dil
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Theoretical Description ◽  
Late Time ◽  
Dynamical Structure ◽  
Dark Sector ◽  
Accelerating Expansion ◽  
Stable Attractor ◽  
The Universe

In this paper, we propose a new approach to study the dark sector of the universe by considering the dark energy as an emergingq-deformed bosonic scalar field which is not only interacting with the dark matter, but also nonminimally coupled to gravity, in the framework of standard Einsteinian gravity. In order to analyze the dynamic of the system, we first give the quantum field theoretical description of theq-deformed scalar field dark energy and then construct the action and the dynamical structure of this interacting and nonminimally coupled dark sector. As a second issue, we perform the phase-space analysis of the model to check the reliability of our proposal by searching the stable attractor solutions implying the late-time accelerating expansion phase of the universe.

scholarly journals Dynamics of Generalized Tachyon Field in Teleparallel Gravity

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Behnaz Fazlpour ◽  
Ali Banijamali
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Dark Energy Model ◽  
Teleparallel Gravity ◽  
Energy Model ◽  
Tachyon Field ◽  
Coincidence Problem

We study dynamics of generalized tachyon scalar field in the framework of teleparallel gravity. This model is an extension of tachyonic teleparallel dark energy model which has been proposed by Banijamali and Fazlpour (2012). In contrast with tachyonic teleparallel dark energy model that has no scaling attractors, here we find some scaling attractors which means that the cosmological coincidence problem can be alleviated. Scaling attractors are presented for both interacting and noninteracting dark energy and dark matter cases.

scholarly journals Dark Energy and Dark Matter Interaction: Kernels of Volterra Type and Coincidence Problem

Symmetry ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 411 ◽  
Author(s):  
Alexander Balakin ◽  
Alexei Ilin
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Exact Solutions ◽  
Gravitational Interaction ◽  
Solvable Model ◽  
Fading Memory ◽  
Dark Sector ◽  
Coincidence Problem ◽  
Volterra Type ◽  
Volterra Type Operator

We study a new exactly solvable model of coupling of the Dark Energy and Dark Matter, in the framework of which the kernel of non-gravitational interaction is presented by the integral Volterra-type operator well-known in the classical theory of fading memory. Exact solutions of this isotropic homogeneous cosmological model were classified with respect to the sign of the discriminant of the cubic characteristic polynomial associated with the key equation of the model. Energy-density scalars of the Dark Energy and Dark Matter, the Hubble function and acceleration parameter are presented explicitly; the scale factor is found in quadratures. Asymptotic analysis of the exact solutions has shown that the Big Rip, Little Rip, Pseudo Rip regimes can be realized with the specific choice of guiding parameters of the model. We show that the Coincidence problem can be solved if we consider the memory effect associated with the interactions in the Dark Sector of the universe.

scholarly journals Dynamics of a scalar field, with a double exponential potential, interacting with dark matter

2015 ◽  
Vol 24 (08) ◽  
pp. 1550068 ◽  
Author(s):  
Vartika Gupta ◽  
Rakesh Kabir ◽  
Amitabha Mukherjee ◽  
Daksh Lohiya
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Effective Potential ◽  
Cosmological Evolution ◽  
Late Time ◽  
Exponential Potential ◽  
Double Exponential

We study the interaction between dark matter and dark energy, with dark energy described by a scalar field having a double exponential effective potential. We discover conditions under which such a scalar field driven solution is a late time attractor. We observe a realistic cosmological evolution which consists of sequential stages of dominance of radiation, matter and dark energy, respectively.

Effective masses in a dense fermion background — Applied to neutrinos, dark matter and dark energy

2014 ◽  
Vol 29 (21) ◽  
pp. 1444010
Author(s):  
Bruce H. J. McKellar ◽  
T. J. Goldman ◽  
G. J. Stephenson
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Effective Mass ◽  
Negative Pressure ◽  
Expectation Value ◽  
Effective Masses ◽  
Neutrino Astrophysics

If fermions interact with a scalar field, and there are many fermions present the scalar field may develop an expectation value and generate an effective mass for the fermions. This can lead to the formation of fermion clusters, which could be relevant for neutrino astrophysics and for dark matter astrophysics. Because this system may exhibit negative pressure, it also leads to a model of dark energy.

scholarly journals FERMIONIC AND SCALAR FIELDS AS SOURCES OF INTERACTING DARK MATTER–DARK ENERGY

2011 ◽  
Vol 20 (13) ◽  
pp. 2543-2558 ◽  
Author(s):  
SAMUEL LEPE ◽  
JAVIER LORCA ◽  
FRANCISCO PEÑA ◽  
YERKO VÁSQUEZ
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Analytical Solution ◽  
Scalar Fields ◽  
Nonminimal Coupling ◽  
Field Equations ◽  
Fermionic Field ◽  
Minimal Coupling ◽  
Constant Type

From a variational action with nonminimal coupling with a scalar field and classical scalar and fermionic interaction, cosmological field equations can be obtained. Imposing a Friedmann–Lemaître–Robertson–Walker (FLRW) metric, the equations lead directly to a cosmological model consisting of two interacting fluids, where the scalar field fluid is interpreted as dark energy and the fermionic field fluid is interpreted as dark matter. Several cases were studied analytically and numerically. An important feature of the non-minimal coupling is that it allows crossing the barrier from a quintessence to phantom behavior. The insensitivity of the solutions to one of the parameters of the model permits it to find an almost analytical solution for the cosmological constant type of universe.

scholarly journals INTERACTION BETWEEN DARK ENERGY AND DARK MATTER: OBSERVATIONAL CONSTRAINTS FROM OHD, BAO, CMB AND SNe Ia

2013 ◽  
Vol 22 (14) ◽  
pp. 1350082 ◽  
Author(s):  
SHUO CAO ◽  
NAN LIANG
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Observational Constraints ◽  
Coincidence Problem ◽  
Cosmological Constraints ◽  
Coincidence Index ◽  
Acceleration Of The Universe ◽  
Interaction Term ◽  
Negative Coupling ◽  
The Universe

In order to test if there is energy transfer between dark energy (DE) and dark matter (DM), we investigate cosmological constraints on two forms of nontrivial interaction between the DM sector and the sector responsible for the acceleration of the universe, in light of the newly revised observations including OHD, CMB, BAO and SNe Ia. More precisely, we find the same tendencies for both phenomenological forms of the interaction term Q = 3γHρ, i.e. the parameter γ to be a small number, |γ| ≈ 10-2. However, concerning the sign of the interaction parameter, we observe that γ > 0 when the interaction between dark sectors is proportional to the energy density of dust matter, whereas the negative coupling (γ < 0) is preferred by observations when the interaction term is proportional to DE density. We further discuss two possible explanations to this incompatibility and apply a quantitative criteria to judge the severity of the coincidence problem. Results suggest that the γm IDE model with a positive coupling may alleviate the coincidence problem, since its coincidence index C is smaller than that for the γd IDE model, the interacting quintessence and phantom models by four orders of magnitude.

scholarly journals Emergent Universe as an interaction in the dark sector

2017 ◽  
Vol 32 (28) ◽  
pp. 1750152
Author(s):  
Emiliano Marachlian ◽  
I. E. Sánchez G. ◽  
Osvaldo P. Santillán
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Linear Equation ◽  
Vacuum Energy ◽  
Cosmological Parameters ◽  
Emergent Universe ◽  
Dark Sector ◽  
Cosmological Scenario ◽  
Friedmann Robertson Walker

A cosmological scenario where dark matter interacts with a variable vacuum energy for a spatially flat Friedmann–Robertson–Walker (FRW) spacetime is proposed and analyzed to show that with a linear equation of state and a particular interaction in the dark sector it is possible to get a model of an Emergent Universe. In addition, the viability of two particular models is studied by taking into account the recent observations. The updated observational Hubble data and the JLA supernovae data are used in order to constraint the cosmological parameters of the models and estimate the amount of dark energy in the radiation era. It is shown that the two models fulfil the severe bounds of [Formula: see text] at the 2[Formula: see text] level of Planck.

scholarly journals The Dark Sector in the Baryon Phase Transition Cosmology

2019 ◽  
Author(s):  
Frederick J. Mayer
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Model ◽  
Dark Sector

This brief communication considers and illustrates dark matter and dark energy within the Baryon Phase Transition (BPT) cosmological model as well as some experiments that may confirm (or deny) the validity of the model.

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