scholarly journals Matter production effects and interacting scenario within a reconstructed mimetic cosmology for late times

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Víctor H. Cárdenas ◽  
Miguel Cruz ◽  
Samuel Lepe
Keyword(s):  
Dark Sector ◽  
Cosmic Expansion ◽  
Phantom Divide ◽  
Cosmic Evolution ◽  
Matter Production ◽  
Proposed Model ◽  
Phantom Dark Energy ◽  
Effective Level ◽  
Interaction Term ◽  
Production Effects

AbstractIn this work we explore two possible scenarios that can be considered to extend a recent proposed model by the authors known as reconstructed mimetic cosmology. This study is complemented with an statistical analysis for each case. The first scenario considers the inclusion of matter production as a possible source of cosmic expansion in the reconstructed mimetic model, at effective level was found that this construction can cross the phantom divide, the model evolves from quintessence to phantom dark energy. The second scenario corresponds to a construction of an interacting scheme for the dark sector which is described by the unified mimetic model. The resulting interaction term (not imposed by an Ansatz), Q, exhibits changes of sign leading to the violation of the second law along the cosmic evolution and non adiabaticity; the temperatures for the components of the dark sector are computed and such components are shown to be out of thermal equilibrium.

scholarly journals UNIVERSE WITH HOLOGRAPHIC DARK ENERGY

MOMENTO ◽  
2020 ◽  
pp. 1-10
Author(s):  
Carlos Rodriguez-Benites ◽  
Mauricio Cataldo ◽  
Marcial Vásquez-Arteaga
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Cold Dark Matter ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Holographic Dark Energy Model ◽  
Dark Sector ◽  
Algebraic Expressions ◽  
Proposed Model ◽  
Λcdm Model

In this work we explore a Holographic Dark Energy Model in a flat Friedmann-LemaÎtre-Robertson-Walker Universe, which contains baryons, radiation, cold dark matter and dark energy within the framework of General Relativity. Furthermore, we consider three types of phenomenological interactions in the dark sector. With the proposed model we obtained the algebraic expressions for the cosmological parameters of our interest: the deceleration and coincidence parameters. Likewise, we graphically compare the proposed model with the ΛCDM model.

scholarly journals Cosmological signatures of dark sector physics: the evolution of haloes and spin alignment

2020 ◽  
Vol 492 (2) ◽  
pp. 2369-2382 ◽  
Author(s):  
Absem W Jibrail ◽  
Pascal J Elahi ◽  
Geraint F Lewis
Keyword(s):  
Dark Matter ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Dark Sector ◽  
Large Scale Structures ◽  
Cosmic Evolution ◽  
The Standard Model ◽  
Scale Structures ◽  
And Migration ◽  
Matter Energy

ABSTRACT The standard cosmological paradigm currently lacks a detailed account of physics in the dark sector, the dark matter and energy that dominate cosmic evolution. In this paper, we consider the distinguishing factors between three alternative models – warm dark matter, quintessence, and coupled dark matter–energy – and lambda cold dark matter (ΛCDM) through numerical simulations of cosmological structure formation. Key halo statistics – halo spin/velocity alignment between large-scale structure and neighbouring haloes, halo formation time, and migration – were compared across cosmologies within the redshift range 0 ≤ z ≤ 2.98. We found the alignment of halo motion and spin to large-scale structures and neighbouring haloes to be similar in all cosmologies for a range of redshifts. The search was extended to low-density regions, avoiding non-linear disturbances of halo spins, yet very similar alignment trends were found between cosmologies, which are difficult to characterize and use as a probe of cosmology. We found that haloes in quintessence cosmologies form earlier than their ΛCDM counterparts. Relating this to the fact that such haloes originate in high-density regions, such findings could hold clues to distinguishing factors for the quintessence cosmology from the standard model. However, in general, halo statistics are not an accurate probe of the dark sector physics.

Role of collisional matter in the framework of extended teleparallel theory

2020 ◽  
Vol 29 (15) ◽  
pp. 2050099
Author(s):  
Muhammad Zeeshan ◽  
M. Zubair ◽  
Rabia Saleem
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Power Law ◽  
Phantom Divide ◽  
Evolutionary Scenario ◽  
Cosmic Evolution ◽  
Phantom Divide Line ◽  
Teleparallel Theory ◽  
Crossing Of Phantom Divide

The purpose of this work is to examine the cosmic evolution in the presence of collisional matter (CM) with and without radiations in a modified Teleparallel theory involving a generic function [Formula: see text] which depends on the scalar torsion [Formula: see text] and the boundary term associated to the divergence of torsion [Formula: see text]. We select seven novel [Formula: see text] models including power law, logarithmic models and exponential models, some of these reported in [S. Bahamonde, M. Zubair and G. Abbas, Phys. Dark Univ. 19 (2018) 78; S. Bahamonde and S. Capozziello, The Eur. Phys. J. C. 77 (2017) 107; C. Escamilla-Rivera and J. L. Said, Class. Quantum Grav. 37 (2020) 165002] and discuss the evolutionary scenario. The behavior of deceleration parameter [Formula: see text], Hubble parameter [Formula: see text], Equation-of-state (EoS) for dark energy (DE) and effective EoS is presented. [Formula: see text]CDM epoch and crossing of phantom divide line (approaching to phantom era) is observed in scenarios like noncollisional matter (NCM) with radiation, CM with and without radiation. Results are found to be adequate with recent cosmic observations.

THE MODIFIED CHAPLYGIN GAS AS A UNIFIED DARK SECTOR MODEL

2007 ◽  
Vol 22 (11) ◽  
pp. 783-790 ◽  
Author(s):  
YABO WU ◽  
SONG LI ◽  
JIANBO LU ◽  
XIUYI YANG
Keyword(s):  
Dark Energy ◽  
State Parameter ◽  
Chaplygin Gas ◽  
Modified Chaplygin Gas ◽  
Dark Sector ◽  
Phantom Divide ◽  
Sector Model ◽  
Energy Models ◽  
Big Rip ◽  
The Future

A modified Chaplygin gas (MCG) model of unifying dark energy and dark matter is considered in this paper. Concretely, the evolution of such a unified dark sector model is studied and the statefinder diagnostic to the MCG model is performed in our model. By analysis, it is shown that the state parameter of dark energy can cross the so-called phantom divide ω = -1, the behavior of MCG will be like ΛCDM in the future and therefore our universe will not end up with Big Rip in the future. In addition, we plot the evolution trajectory of the MCG model in the statefinder parameter r–s plane and show the discrimination between this scenario and other dark energy models.

scholarly journals Heavy dark matter through the dilaton portal

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Benjamin Fuks ◽  
Mark D. Goodsell ◽  
Dong Woo Kang ◽  
Pyungwon Ko ◽  
Seung J. Lee ◽  
...  
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
Effective Field ◽  
Matter Density ◽  
Field Theories ◽  
Majorana Fermion ◽  
Dark Sector ◽  
Gauge Invariant ◽  
Matter Production ◽  
Invariant Formulation

Abstract We re-examine current and future constraints on a heavy dilaton coupled to a simple dark sector consisting of a Majorana fermion or a Stückelberg vector field. We include three different treatments of dilaton-Higgs mixing, paying particular attention to a gauge-invariant formulation of the model. Moreover, we also invite readers to re-examine effective field theories of vector dark matter, which we show are missing important terms. Along with the latest Higgs coupling data, heavy scalar search results, and dark matter density/direct detection constraints, we study the LHC bounds on the model and estimate the prospects of dark matter production at the future HL-LHC and 100 TeV FCC colliders. We additionally compute novel perturbative unitarity constraints involving vector dark matter, dilaton and gluon scattering.

scholarly journals SCALAR, FOUR VOLUME AND HOLOGRAPHIC DARK ENERGY

2012 ◽  
Vol 10 ◽  
pp. 95-106 ◽  
Author(s):  
CHANGJUN GAO
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Holographic Dark Energy ◽  
Specific Form ◽  
Holographic Dark Energy Model ◽  
Cosmic Evolution ◽  
Dimensional Spacetime ◽  
Phantom Dark Energy ◽  
Acceleration Of The Universe ◽  
The Universe

We explore the cosmic evolution of a scalar field which is identified with the four dimensional spacetime volume. Given a specific form for the Lagrangian of the scalar field, a new holographic dark energy model is present. The energy density of dark energy is reversely proportional to the square of the radius of the cosmic null hypersurface which is present as a new infrared cutoff for the Universe. We find this holographic dark energy belongs to the phantom dark energy for some appropriate parameters in order to interpret the current acceleration of the Universe.

scholarly journals Cosmological Consequences of a Parametrized Equation of State

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1009
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
Sidra Saleem ◽  
Kazuharu Bamba ◽  
Riffat Jabeen
Keyword(s):  
Equation Of State ◽  
Taylor Series ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Accelerating Universe ◽  
Isotropic Model ◽  
Om Diagnostic ◽  
Cosmic Evolution ◽  
Interaction Term ◽  
Chern Simons

We explore the cosmic evolution of the accelerating universe in the framework of dynamical Chern–Simons modified gravity in an interacting scenario by taking the flat homogeneous and isotropic model. For this purpose, we take some parametrizations of the equation of state parameter. This parametrization may be a Taylor series extension in the redshift, a Taylor series extension in the scale factor or any other general parametrization of ω . We analyze the interaction term which calculates the action of interaction between dark matter and dark energy. We explore various cosmological parameters such as deceleration parameter, squared speed of sound, Om-diagnostic and statefinder via graphical behavior.

scholarly journals Baryonic Force for Accelerated Cosmic Expansion and Generalized U1b Gauge Symmetry in Particle-Cosmology

2018 ◽  
Vol 168 ◽  
pp. 04004
Author(s):  
Mehbub Khan ◽  
Yun Hao ◽  
Jong-Ping Hsu
Keyword(s):  
Gauge Field ◽  
Doppler Frequency ◽  
Late Time ◽  
Linear Potential ◽  
Frequency Shifts ◽  
Yang Mills ◽  
Cosmic Expansion ◽  
Cosmic Evolution ◽  
Linear Force ◽  
Doppler Frequency Shifts

Based on baryon charge conservation and a generalized Yang-Mills symmetry for Abelian (and non-Abelian) groups, we discuss a new baryonic gauge field and its linear potential for two point-like baryon charges. The force between two point-like baryons is repulsive, extremely weak and independent of distance. However, for two extended baryonic systems, we have a dominant linear force α r. Thus, only in the later stage of the cosmic evolution, when two baryonic galaxies are separated by an extremely large distance, the new repulsive baryonic force can overcome the gravitational attractive force. Such a model provides a gauge-field-theoretic understanding of the late-time accelerated cosmic expansion. The baryonic force can be tested by measuring the accelerated Wu-Doppler frequency shifts of supernovae at different distances.

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