Article
Astronomy & Astrophysics
Muhammad F. A. R. Sakti, Anto Sulaksono
Summary: The researcher constructed an exact star solution of a dark energy star, analyzed its energy conditions, and found that it may violate the strong energy condition under specific circumstances. The study also discovered stability issues in terms of convective motion and gravitational cracking for the dark energy star.
Article
Astronomy & Astrophysics
Soumya Chakraborty, Sudip Mishra, Subenoy Chakraborty
Summary: This work illustrates the application of dynamical system analysis in the context of cosmology, investigating the role of dark energy and dark matter in cosmic evolution. The stability and bifurcation analysis are performed to study cosmological phase transitions.
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2022)
Article
Astronomy & Astrophysics
Daniele Oriti, Xiankai Pang
Summary: The analysis of emergent cosmological dynamics in mean field hydrodynamics of quantum gravity condensates reveals accelerated expansion of the universe at both early and late times. Although it does not support a compelling inflationary scenario in the early universe, it naturally produces a phantom-like dark energy dynamics at late times, which crosses the phantom divide and avoids any Big Rip singularity, approaching a de Sitter universe asymptotically.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
Imanol Albarran, Mariam Bouhmadi-Lopez, Joao Marto
Summary: The paper analyzes the phenomenological effects of a varying Dark Energy effective speed of sound parameter on cosmological perturbations of three phantom DE models. The study forecasts potential abrupt future events and demonstrates that different parameter values can lead to variations in the matter power spectrum.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Multidisciplinary
Eleonora Di Valentino, Ankan Mukherjee, Anjan A. Sen
Summary: The study found that constraints from different combinations of data are consistent with each other and all support phantom crossing in the dark energy sector. The combined data is in agreement with the local measurement by Riess et al.
Article
Astronomy & Astrophysics
Andreas Lymperis
Summary: By investigating the features of a non-metricity scalar Q function, the cosmological implications of f(Q) gravity are explored, and analytical expressions for the dark energy density, equation-of-state, and deceleration parameters are obtained. The study reveals that even in the absence of a cosmological constant, the universe follows the usual thermal history with matter and dark energy eras, and the dark energy equation-of-state parameter remains in the phantom regime. Additionally, the scenario shows excellent agreement with observational data from Supernovae type Ia. Furthermore, it is demonstrated that f(Q) gravity can effectively mimic the behavior of a cosmological constant.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Amine Bouali, Imanol Albarran, Mariam Bouhmadi-Lopez, Ahmed Errahmani, Taoufik Ouali
Summary: This paper examines the interaction between three phantom dark energy models, investigating their impact on cosmological parameters and the presence of singularities and abrupt events. The study focuses on distinguishing these models based on their equations of state and explores the potential of interactions between cold dark matter and dark energy to address issues in standard cosmology. Through the use of a MCMC approach, the cosmological parameters of each model are constrained, and comparisons are made using the corrected AIC(c) tool. The perturbative analysis of phantom DE models based on best fit background parameters is also conducted.
PHYSICS OF THE DARK UNIVERSE
(2021)
Article
Astronomy & Astrophysics
Weiqiang Yang, Supriya Pan, Eleonora Di Valentino, Olga Mena, Alessandro Melchiorri
Summary: Current cosmological data analyses show that a closed universe and interacting scenarios are attractive options for resolving the Hubble constant tension. However, the viability of these scenarios as global solutions to cosmological tensions may be compromised when considering other possible cosmological observations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Mathematical
Bramha Dutta Pandey, Pankaj, Umesh Kumar Sharma
Summary: This paper examines Tsallis holographic dark energy in a flat FLRW universe, with the future event horizon as an IR cutoff. The study observes suitable behavior in the model by analyzing the evolutionary behavior of parameters related to dark energy density and the equation of state. Additionally, efforts are made to reconstruct the potential of the phantom for delta > 1 with lower redshift by examining the dynamics of the scalar field.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2022)
Article
Astronomy & Astrophysics
Safae Dahmani, Amine Bouali, Imad El Bojaddaini, Ahmed Errahmani, Taoufik Ouali
Summary: The discrepancy between Planck data and direct measurements of H0 and S8 has become one of the most intriguing puzzles in cosmology. The tension in H0 has reached 5σ in the context of the standard cosmology model. Exploring physics beyond the standard model is necessary to explain this issue.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
Miguel Cruz, Samuel Lepe, German E. Soto
Summary: In this article, we review a dynamical dark energy model that has rarely been studied in the literature and propose two possible generalizations. By exploring the behavior of the original model and a minimal extension, we find that the cosmic components are related to their parameter states. In order to investigate the phantom regime, we present two dark energy densities inspired by the holographic approach and the emergent entropic forces model. We discover a type-III singularity in the first case and a transition from decelerated to accelerated cosmic expansion in the second proposal, ultimately leading to a de Sitter state.
Article
Astronomy & Astrophysics
Masato Nozawa
Summary: The static and spherically symmetric solutions in the n(≥4)-dimensional Einstein-phantom-scalar system can be classified into three families: the Fisher solution, the Ellis-Gibbons solution, and the Ellis-Bronnikov solution. These solutions are used as seeds to generate corresponding asymptotically (A)dS spacetimes by introducing the potential of the scalar field. Despite having different potentials, each potential is expressed in terms of the superpotential as in supergravity. Specifically, the novel examples of spherical traversable wormholes in the Ellis-Bronnikov class of solutions interpolate two different (A)dS critical points of the (super)potential.
Article
Physics, Multidisciplinary
Jae Hyeok Chang, David E. Kaplan, Surjeet Rajendran, Harikrishnan Ramani, Erwin H. Tanin
Summary: We studied the emission of self-thermalizing light dark sector particles in the solar system. We found that this phenomenon is commonly observed in a dark sector composed of millicharged particles interacting via a dark photon, resulting in a plasma wind with distinctive and predictable signatures.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Kangujam Priyokumar Singh, Pheiroijam Suranjoy Singh
Summary: In this work, a minimally interacting holographic dark energy model is investigated within the framework of the Saez-Ballester Theory, using a spherically symmetric metric. The prediction suggests that the dominant dark energy component in the universe is of phantom type, leading to cosmic doomsday. However, to resolve the incompatibility between the big rip singularity and holographic dark energy, a higher dimensional scenario is employed, replacing the cosmic doomsday with a de-Sitter phase. The model exhibits a slow and uniform change of size during early evolution, which accelerates as time progresses, consistent with current observations of accelerated expansion. The measured values of the Hubble parameter and the dark energy EoS parameter are found to be in agreement with the most recent Planck 2018 result.
CHINESE JOURNAL OF PHYSICS
(2022)
Article
Mathematics, Applied
A. Q. Khan, S. M. Qureshi
Summary: This study investigates the equilibrium points, local and global dynamics, rate of convergence, instability, and boundedness of positive solutions of some rational systems of difference equations. In addition, it explores the local dynamics around equilibrium points of the discrete-time Levin's model as an application in mathematical biology. The obtained results are then numerically verified.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
