198 citations · 1.8k across the 47 of their papers we have counts for
21 papers · 1 filter
Background-level reconstruction of scalar-field potentials from dark-energy histories and comparison with analytic potential families
Shahnawaz A. Adil, Miguel A. Zapata, Özgür Akarsu +1
We present a unified \emph{background-level} framework that maps a prescribed late-time dark-energy density history onto an effective scalar-field description in a…
Probing dynamical dark energy with late-time data: Evidence, tensions, and the limits of the CDM framework
Tengpeng Xu, Suresh Kumar, Yun Chen +2
We test the dynamical dark-energy CDM (CPL) framework against CDM using CMB anisotropies and lensing together with DESI DR2, SDSS-IV, transverse/angular BAO (BAOtr), and…
Linear matter density perturbations in the CDM model: Examining growth dynamics and addressing the tension
Özgür Akarsu, Arman Çam, Evangelos A. Paraskevas +1
We investigate linear matter density perturbations in the CDM, in which the is replaced by late-time () mirror AdS-dS transition, resulting in distinct growt…
Mapping the CDM scenario to modified gravity: Effects on structure growth rate
Mateus S. Souza, Ana M. Barcelos, Rafael C. Nunes +2
The concept of a rapidly sign-switching cosmological constant, interpreted as a mirror AdS-dS transition in the late universe and known as the CDM, has significantly imp…
Exploring new physics in the late Universe's expansion through non-parametric inference
Miguel A. Sabogal, Özgür Akarsu, Alexander Bonilla +2
In this study, we investigate deviations from the Planck-CDM model in the late universe () using the Gaussian Processes method, with minimal assumptions. Our goa…
CDM cosmology: Alleviating major cosmological tensions by predicting standard neutrino properties
Anita Yadav, Suresh Kumar, Cihad Kibris +1
We investigate a two-parameter extension of the CDM model by allowing variations in the effective number of neutrino species and their total mass $\sum m_ν…
Cosmological constraints on CDM scenario in a type II minimally modified gravity
Özgür Akarsu, Antonio De Felice, Eleonora Di Valentino +5
The idea of a rapid sign-switching cosmological constant (mirror AdS-dS transition) in the late universe at , known as the CDM model, has significantly improve…
CDM cosmology from a type-II minimally modified gravity
Özgür Akarsu, Antonio De Felice, Eleonora Di Valentino +5
We integrate CDM, a promising scenario for alleviating cosmological tensions, into VCDM, a type-II minimally modified gravity. This promotes the scenario to a fully pred…
Transition dynamics in the CDM model: Implications for bound cosmic structures
Evangelos A. Paraskevas, Arman Cam, Leandros Perivolaropoulos +1
We explore the predictions of CDM, a novel framework suggesting a rapid anti-de Sitter (AdS) to de Sitter (dS) vacua transition in the late Universe, on bound cosmic str…
CDM Tensions: Localising Missing Physics through Consistency Checks
Özgür Akarsu, Eoin Ó Colgáin, Anjan A. Sen +1
CDM tensions are by definition model dependent; one sees anomalies through the prism of CDM. Thus, progress towards tension resolution necessitates checking the consistency o…
Quadratic energy-momentum squared gravity: constraints from big bang nucleosynthesis
Ozgur Akarsu, Mariam Bouhmadi-López, Nihan Katirci +1
In this work, we extend the standard cosmological model within the quadratic energy-momentum squared gravity (qEMSG) framework, introducing a nonminimal interaction between the usu…
Omnipotent dark energy: A phenomenological answer to the Hubble tension
Shahnawaz A. Adil, Ozgur Akarsu, Eleonora Di Valentino +4
This paper introduces the class of omnipotent dark energy (DE) models characterized by nonmonotonic energy densities that are capable of attaining negative values with correspondin…
Model-independent reconstruction of the Interacting Dark Energy Kernel: Binned and Gaussian process
Luis A. Escamilla, Ozgur Akarsu, Eleonora Di Valentino +1
The cosmological dark sector remains an enigma, offering numerous possibilities for exploration. One particularly intriguing option is the (non-minimal) interaction scenario betwee…
Relaxing cosmological tensions with a sign switching cosmological constant: Improved results with Planck, BAO, and Pantheon data
Ozgur Akarsu, Suresh Kumar, Emre Ozulker +2
We present a further observational analysis of the CDM model proposed in Akarsu et al. [Phys. Rev. D 104, 123512 (2021)]. This model is based on the recent conjecture su…
Inevitable manifestation of wiggles in the expansion of the late Universe
Ozgur Akarsu, Eoin O. Colgain, Emre Ozulker +2
Using the fact that the comoving angular diameter distance to the last scattering surface is strictly constrained almost model independently, we show that, for any model agreeing w…
Testing spatial curvature and anisotropic expansion on top of the CDM model
Ozgur Akarsu, Eleonora Di Valentino, Suresh Kumar +2
We explore the possible advantages of extending the CDM model by more realistic backgrounds compared to its spatially flat RW spacetime assumption, while preserving the underpin…
Relaxing cosmological tensions with a sign switching cosmological constant
Ozgur Akarsu, Suresh Kumar, Emre Ozulker +1
Inspired by the recent conjecture originated from graduated dark energy that the Universe has recently transitioned from anti-de Sitter vacua to de Sitter vacua, we extend the C…
Rastall gravity extension of the standard CDM model: theoretical features and observational constraints
Ozgur Akarsu, Nihan Katirci, Suresh Kumar +3
We present a detailed investigation of the Rastall gravity extension of the standard CDM model. We review the model for two simultaneous modifications of different nature in the…
Graduated dark energy: Observational hints of a spontaneous sign switch in the cosmological constant
Ozgur Akarsu, John D. Barrow, Luis A. Escamilla +1
We study the cosmological constant () in the standard CDM model by introducing the \textit{graduated dark energy} (gDE) characterised by a minimal dynamical deviation from th…
Broken scale invariance, -attractors and vector impurity
Ozgur Akarsu, Sibel Boran, Emre O. Kahya +2
We show that if the -attractor model is realized by the spontaneous breaking of the scale symmetry, then the stability and the dynamics of the vector field that gauges the scale…
A divergence-free parametrization for dynamical dark energy
Ozgur Akarsu, Tekin Dereli, J. Alberto Vazquez
We introduce a new parametrization for the dark energy, led by the same idea to the linear expansion of the equation of state in scale factor and in redshift , which diverge…