Abstract We critically examine the state of current constraints on dark energy (DE) equation (EoS) w . Our study is motivated by observation that, while broadly consistent with cosmological constant value = -1, several independent probes appear to point towards a slightly phantom EoS ( ∼ -1.03) which, if confirmed, could have important implications for Hubble tension. pay attention apparent preference DE from Planck Cosmic Microwave Background (CMB) data alone, whose origin we in detail and...

The Hubble tension is inherently multidimensional and bears important implications for parameters beyond H0. We discuss the key role of matter density parameter Ωm physical cold dark ωc. argue that once baryon ωb are calibrated, through acoustic oscillations (BAO) and/or type Ia supernovae (SNeIa) Ωm, via big bang nucleosynthesis ωb, any model raising H0 requires ωc and, under minimal assumptions, also clustering S8. explicitly verify this behavior holds when analyzing recent BAO SNeIa data....

The main aim of this work is to use a model-independent approach, along with late-time observational probes, reconstruct the dark energy (DE) equation state <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>w</a:mi></a:mrow><a:mrow><a:mi>DE</a:mi></a:mrow></a:msub><a:mo stretchy="false">(</a:mo><a:mi>z</a:mi><a:mo stretchy="false">)</a:mo></a:mrow></a:math>. Our analysis showed that, for late time universe, <e:math...

We study the cosmological constant ($\Lambda$) in standard $\Lambda$CDM model by introducing \textit{graduated dark energy} (gDE) characterised a minimal dynamical deviation from null inertial mass density of $\Lambda$ form $\rho_{\rm inert}\propto \rho^{\lambda}<0$ with $\lambda<1$ being ratio two odd integers, for which its energy $\rho$ dynamically takes negative values finite past. For large $\lambda$, it creates phenomenological described smooth function that approximately describes...

Abstract The cosmological dark sector remains an enigma, offering numerous possibilities for exploration. One particularly intriguing option is the (non-minimal) interaction scenario between matter and energy. In this paper, to investigate scenario, we have implemented Binned Gaussian model-independent reconstructions kernel alongside equation of state; while using data from BAOs, Pantheon+ Cosmic Chronometers. addition reconstruction process, conducted a model selection analyze how our...

Bayesian statistics and Markov Chain Monte Carlo (MCMC) algorithms have found their place in the field of Cosmology. They become important mathematical numerical tools, especially parameter estimation model comparison. In this paper, we review some fundamental concepts to understand then introduce MCMC samplers that allow us perform inference procedure. We also a general description standard cosmological model, known as $\Lambda$CDM along with several alternatives, current datasets coming...

The main aim of this paper is to perform a model comparison for some reconstructions the key properties that describe dark energy Universe i.e. density and equation state (EoS). We carry out process by using binning linear interpolation methodologies, on top that, we incorporate correlation function mechanism. An extension two them was also introduced, where internal amplitudes are allowed vary in height as well position. were made with data from Hubble parameter, Supernovae Type Ia Baryon...

ABSTRACT It is a fact that the universe lives on gravitational wave background (GWB), which extra space–time energy not contained in Einstein’s field equations. In previous work, this treated as property of and source. With mind, new model was developed incorporates to explain current accelerated expansion where GWB incorporated by extending equations $R_{\mu \nu }-\frac{1}{2}Rg_{\mu }+\frac{2\pi ^2}{{\lambda }^2}g_{\mu }= \kappa ^2 T_{\mu }$, λ Compton wavelength cosmological scale...

We parameterize the Hubble function by adding Hermitian wavelets to radius of $\Lambda$CDM. This allows us build functions that oscillate around $\Lambda$CDM at late times without modifying its angular diameter distance last scattering. perform parameter inference and model selection procedures on these new background level. In our analyses consisting a wide variety cosmological observations, we find baryon acoustic oscillations (BAO) data play crucial role in determining constraints wavelet...

We critically examine the state of current constraints on dark energy (DE) equation (EoS) $w$. Our study is partially motivated by observation that, while broadly consistent with cosmological constant value $w=-1$, several independent probes appear to point towards a slightly phantom EoS ($w \sim -1.03$). pay attention apparent preference for DE from Planck Cosmic Microwave Background (CMB) data alone, whose origin we in detail and attribute wide range (physical geometrical) effects. deem...

The main aim of this work is to use a model-independent approach, along with late-time observational probes, reconstruct the dark energy (DE) equation state $w_{\rm DE}(z)$. Our analysis showed that, for late time universe, DE}$ deviates from being constant but in contrast exhibits an oscillatory behavior, hence both quintessence ($w_{\rm DE}> -1$) and phantom DE} < regimes are equally allowed. In order portray we explored various parametrizations identified closest approximation based on...

We investigate a modified cosmological model aimed at addressing the Hubble tension, considering revised dynamics in late Universe. The introduces parameter $c$ affecting evolution equations, motivated by Poisson algebra inspired effective Loop Quantum Cosmology. Our analysis includes diverse background datasets such as Cosmic Chronometers, Pantheon+ Type Ia Supernovae (with and without SH0ES calibration), SDSS, DESY6 DESI Baryon Acoustic Oscillations, information of Microwave Background....

The current accelerated expansion of the Universe remains one most intriguing topics in modern cosmology, driving search for innovative statistical techniques. Recent advancements machine learning have significantly enhanced its application across various scientific fields, including physics, and particularly where data analysis plays a crucial role problem-solving. In this work, non-parametric regression method with Gaussian processes is presented along several applications to reconstruct...

The current accelerated expansion of the Universe remains ones most intriguing topics in modern cosmology, driving search for innovative statistical techniques. Recent advancements machine learning have significantly enhanced its application across various scientific fields, including physics, and particularly where data analysis plays a crucial role problem-solving. In this work, non-parametric regression method with Gaussian processes is presented along several applications to reconstruct...

The main aim of this paper is to perform a model comparison for some reconstructions the key properties that describe dark energy Universe i.e. density and equation state (EoS). We carry out process by using binning linear interpolation methodologies, on top that, we incorporate correlation function mechanism. An extension two them was also introduced, where internal amplitudes are allowed vary in height as well position. were made with data from Hubble parameter, Supernovae Type Ia Baryon...

The cosmological dark sector remains an enigma, offering numerous possibilities for exploration. One particularly intriguing option is the (non-minimal) interaction scenario between matter and energy. In this paper, to investigate scenario, we have implemented Binned Gaussian model-independent reconstructions kernel alongside equation of state; while using data from BAOs, Pantheon+ Cosmic Chronometers. addition reconstruction process, conducted a model selection analyze how our methodology...

It is a fact that the universe lives on Gravitational Wave Background (GWB), which it may be in form of extra energy, not contained Einstein's field equations. In \cite{Matos:2021jef}, new model was developed to explain current accelerating expansion where GWB incorporated by extending equations $R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}+\frac{2\pi^2}{{\lambda}^2}g_{\mu\nu}=\kappa ^2 T_{\mu\nu}$, ${\lambda}$ Compton wavelength graviton. present work we show this extended agrees very well with...

It is a fact that the universe lives on Gravitational Wave Background (GWB), which it may be in form of extra energy, not contained Einstein’s field equations. In [1], new model was developed to explain current accelerating expansion where GWB incorporated by extending equations to, λ Compton wavelength graviton. present work we show this extended agrees very well with observations Cosmic chronometers, Baryon Acoustic Oscillations and Pantheon SN type Ia, reproducing observational data ∆χ2 =...