Article
Physics, Mathematical
Abdul Jawad, Sabir Hussain
Summary: This paper investigates the Tsallis holographic dark energy model in different cosmological contexts, analyzing various cosmological parameters and planes, and comparing them with the Planck data to draw conclusions about the consistency of cosmic expansion.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2021)
Article
Physics, Multidisciplinary
Ahmad Sheykhi, Maral Sahebi Hamedan
Summary: The thermodynamics-gravity conjecture suggests a strong connection between the gravitational field equations and the first law of thermodynamics, meaning any changes in entropy expression directly impact the field equations. By considering the modified Barrow entropy associated with the apparent horizon, the Friedmann equations are altered as well. This paper explores the implications of this modification on the holographic dark energy (HDE) model, highlighting changes in energy density and the Friedmann equations. The study also investigates the cosmological consequences of using the Hubble horizon and future event horizon as infrared cutoffs, including interactions between dark matter (DM) and dark energy (DE), and the impact of the Barrow exponent on the cosmological behavior of HDE, such as crossing the phantom line and shifting the universe phase transition time.
Article
Astronomy & Astrophysics
Alexander B. Balakin, Aliya A. Galimova
Summary: The study focuses on the extension of axion-dilaton-aether electrodynamics within the framework of the Einstein-Maxwell-axion-aether theory, applied to a specific cosmological model. A new type of dynamic equilibrium state of the axion-photon system is proposed and examined in the context of electrodynamics with axionic nonlinearity. The nonlinear axion-photon interactions are shown to have the ability to mimic dilaton-photon coupling, with discussions on the stability of the model concerning homogeneous fluctuations of the axion field.
Article
Astronomy & Astrophysics
Antonio De Felice, Shinji Mukohyama
Summary: This paper introduces a new cosmological framework integrating dark matter into a minimally modified gravity model, maintaining the same number of gravitational degrees of freedom through a series of transformations. The framework includes two time-dependent free functions to achieve desired evolutions of Hubble expansion rate and effective gravitational constant for dark matter.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Abdul Jawad, Zain ul Abideen, Shamaila Rani
Summary: In this paper, the cosmic analysis of the Kaniadakis holographic dark energy model is investigated in the frameworks of f(G) and f(similar to)(T) modified theories of gravity. The functional forms of f(G) and f(similar to)(T) models are reconstructed using a power-law form of scale factor and flat FRW metric. The behavior of these functional forms with respect to their arguments is discussed. Various cosmic parameters are explored using these models to discuss the accelerated expansion of the universe, and consistent results are obtained for specific values of model parameters.
MODERN PHYSICS LETTERS A
(2023)
Article
Physics, Nuclear
Mihai Marciu, Dana Maria Ioan
Summary: This paper extends the basic Einstein-Hilbert action by introducing a non-minimal coupling between the space-time geometry and matter fields. It formulates a cosmological model based on specific associations between the matter energy-momentum tensor and the Einstein tensor. The dynamics of the model and its physical implications are explored through a dynamical system analysis.
Article
Astronomy & Astrophysics
Yuewei Wen, Eva Nesbit, Dragan Huterer, Scott Watson
Summary: Standard cosmological data analyses can't easily determine the presence of modified gravity. This study presents a quantitative mapping showing how modified gravity models appear within standard analyses, reporting specific biases in standard-parameter spaces. The implications for measurements of mass fluctuations are also discussed.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Jiwon Park, Tae Hoon Lee
Summary: In this paper, the authors propose an f(R) gravity model to explain dark energy which can also be applied to a type of galactic dark matter. By constructing f(R) gravitational Lagrangians through a Legendre transform from scalar-tensor theories, the future behavior of the late-time accelerating Universe as well as the subsequent behavior of an inflation model are studied. Moreover, possible relations to galactic dark matter are discussed, with a spherically symmetric solution obtained for the static metric in the f(R) model.
MODERN PHYSICS LETTERS A
(2023)
Article
Physics, Particles & Fields
Armin van de Venn, David Vasak, Johannes Kirsch, Juergen Struckmeier
Summary: The paper investigates the implications of metric compatible covariant canonical gauge theory of gravity on cosmological scales. The resulting equations of motion in a Friedmann-Lemaitre-Robertson-Walker Universe are derived for a totally anti-symmetric torsion tensor. The modifications of the Friedmann equations, equivalent to spatial curvature, are shown in the limit of a vanishing quadratic Riemann-Cartan term and are further investigated in the early and late times of the Universe's history.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Artyom V. Astashenok, Sergey D. Odintsov, Vasilis K. Oikonomou
Summary: In this paper, we investigate realistic models of compact objects, focusing on neutron and strange stars composed of dense matter and dark energy. We consider different scenarios for dark energy, including simple fluid or scalar field interacting with matter, modified gravity combined with dark energy, and dark energy as scalar field non-minimally interacting with gravity.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
S. D. Odintsov, V. K. Oikonomou
Summary: The deformed R-2 model closely approximates the R-2 model during inflation, but exhibits stronger gravity and can incorporate an early dark energy term to control late-time dynamics.
Article
Astronomy & Astrophysics
Giovanni Gandolfi, Andrea Lapi, Stefano Liberati
Summary: The study focuses on self-gravitating equilibria of dark matter (DM) halos with non-minimal coupling to gravity, which results in the development of an inner core and a shape closely following the Burkert profile. This non-minimal coupling allows for mass distribution that fits well with rotation curves of dwarf, DM-dominated galaxies and is consistent with observed scaling relations among different galaxies.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Alexander Ganz, Chunshan Lin
Summary: This study investigates the structure formation in the effective field theory of holographic dark energy. It is found that the equation of motion for the energy contrast of cold dark matter is the same as the one in general relativity up to the leading order in the small scale limit, under the condition that the equation of state is quintessence-like. However, the effective field theory breaks down when the equation of state becomes phantom-like.
CLASSICAL AND QUANTUM GRAVITY
(2022)
Article
Physics, Particles & Fields
Hassan Firouzjahi, Mohammad Ali Gorji, Shinji Mukohyama, Borna Salehian
Summary: The model introduces a scenario of vector dark matter production during inflation, where the quantum fluctuations of the inflaton field energy are used to explain the observed relic density of dark matter, which can be applicable to a wide range of parameters.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Alexander Ganz
Summary: Minimally modified gravity models use auxiliary constraints to maintain a dynamic cosmological background, with results of linear perturbations being insensitive to constraint details, leading to a modified effective gravitational constant or a non-zero dust sound speed.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)