540 citations · 1.1k across the 20 of their papers we have counts for
21 papers
A Friendly Phantom: Late-time AdS-to-dS transition and cosmological tensions
Özgür Akarsu, Leandros Perivolaropoulos, A. Emrah Yükselci +1
We present Ph-CDM, a phantom-scalar realization within General Relativity of the sign-switching cosmological-constant idea, CDM, in which a phantom scalar evo…
Negative neutrino mass or negative dark energy?
Cihad Kıbrıs, Willem Elbers, Özgür Akarsu +1
Recent cosmological analyses based on DESI and CMB data have revealed a tension between the inferred sum of neutrino masses and the minimum value allowed by neutrino oscillation ex…
Do equation of state parametrizations of dark energy faithfully capture the dynamics of the late universe?
Özgür Akarsu, Maria Caruana, Konstantinos F. Dialektopoulos +3
We investigate how strongly late-time inferences about DE dynamics depend on the functional prior used to represent the expansion history. Using identical late-time combinations of…
Hints of sign-changing scalar field energy density and a transient acceleration phase at from model-agnostic reconstructions
Özgür Akarsu, Maria Caruana, Konstantinos F. Dialektopoulos +3
We present a data-driven reconstruction of the late-time expansion history and its implications for dark-energy dynamics. Modeling the reduced Hubble rate with a node-based Gaussia…
Nonlinear Matter Power Spectrum from relativistic -body Simulations: CDM versus CDM
Özgür Akarsu, Eleonora Di Valentino, Jiří Vyskočil +3
We present relativistic -body simulations of a CDM - sign-switching cosmological constant (CC) - scenario under general relativity and compare its nonlinear matter po…
Updated Constraints on Omnipotent Dark Energy: A Comprehensive Analysis with CMB and BAO Data
Enrico Specogna, Shahnawaz A. Adil, Emre Ozulker +4
In this work, we present updated observational constraints on the parameter space of the DMS20 dark energy model, a member of the omnipotent dark energy (ODE) class. Our analysis c…
The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
Eleonora Di Valentino, Jackson Levi Said, Adam Riess +533
The standard model of cosmology has provided a good phenomenological description of a wide range of observations both at astrophysical and cosmological scales for several decades.…
Exploring the Growth-Index () Tension with CDM
Luis A. Escamilla, Özgür Akarsu, Eleonora Di Valentino +2
Recent observational analyses have revealed a significant tension in the growth index , which characterizes the growth rate of cosmic structures. Specifically, when treating …
Dynamical dark energy with AdS-to-dS and dS-to-dS transitions: Implications for the tension
Özgür Akarsu, Leandros Perivolaropoulos, Anna Tsikoundoura +2
We investigate the dynamics and cosmological implications of dark energy (DE), modeled as a scalar field with a hyperbolic tangent potential that induces a smooth shift in the effe…
CDM model: A promising scenario for alleviation of cosmological tensions
Ozgur Akarsu, Eleonora Di Valentino, Suresh Kumar +3
We present a comprehensive analysis of the CDM model, which explores the recent conjecture suggesting a rapid transition of the Universe from anti-de Sitter vacua to de…
- inflation: Sourced by energy-momentum squared gravity
Seyed Ali Hosseini Mansoori, Fereshteh Felegary, Mahmood Roshan +2
In this paper, we examine chaotic inflation within the context of the energy-momentum squared gravity (EMSG) focusing on the energy-momentum powered gravity (EMPG) that incorporate…
increases with effective redshift in CDM cosmology
Shahnawaz A. Adil, Özgür Akarsu, Mohammad Malekjani +4
Hubble constant and weighted amplitude of matter fluctuations determinations are biased to higher and lower values, respectively, in the late Universe with respect to e…
Cosmological models in scale-independent energy-momentum squared gravity
Ozgur Akarsu, N. Merve Uzun
Scale-independent EMSG is a particular model of energy-momentum squared gravity (EMSG) in which the new terms in the Einstein field equations arising from the EMSG theory enter wit…
Report of the Topical Group on Cosmic Probes of Fundamental Physics for for Snowmass 2021
Rana X. Adhikari, Luis A. Anchordoqui, Ke Fang +118
Cosmic Probes of Fundamental Physics take two primary forms: Very high energy particles (cosmic rays, neutrinos, and gamma rays) and gravitational waves. Already today, these probe…
Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies
Elcio Abdalla, Guillermo Franco Abellán, Amin Aboubrahim +200
In this paper we will list a few important goals that need to be addressed in the next decade, also taking into account the current discordances between the different cosmological…
CDM cosmology with a quiescent anisotropy in a higher dimensional steady state universe
Ozgur Akarsu, Tekin Dereli, Nihan Katirci
In this work, which follows a series of studies on the higher-dimensional steady state universe idea and prepared for Professor Tekin Dereli's Festschrift, we show the influence of…
Cosmology Intertwined II: The Hubble Constant Tension
Eleonora Di Valentino, Luis A. Anchordoqui, Ozgur Akarsu +90
The current cosmological probes have provided a fantastic confirmation of the standard Cold Dark Matter cosmological model, that has been constrained with unprecedented accurac…
Cosmological implications of scale-independent energy-momentum squared gravity: Pseudo nonminimal interactions in dark matter and relativistic relics
Ozgur Akarsu, Nihan Katirci, Suresh Kumar +2
In this paper, we introduce a scale-independent energy-momentum squared gravity (EMSG) that allows different gravitational couplings for different types of sources, which may lead…
Black branes and black strings in the astrophysical and cosmological context
Ozgur Akarsu, Alexey Chopovsky, Alexander Zhuk
We consider Kaluza-Klein models where internal spaces are compact flat or curved Einstein spaces. This background is perturbed by a compact gravitating body with the dust-like equa…
Brane world models with bulk perfect fluid and broken 4D Poincare invariance
Ozgur Akarsu, Alexey Chopovsky, Maxim Eingorn +2
We consider 5D brane world models with broken global 4D Poincar\a'{e} invariance (4D part of the spacetime metric is not conformal to the Minkowski spacetime). The bulk is filled w…
Late Time Acceleration of the 3-Space in a Higher Dimensional Steady State Universe in Dilaton Gravity
Ozgur Akarsu, Tekin Dereli
We present cosmological solutions for (1+3+n)-dimensional steady state universe in dilaton gravity with an arbitrary dilaton coupling constant w and exponential dilaton self-intera…