299 citations · 1.1k across the 42 of their papers we have counts for
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Addressing the DESI DR2 Phantom-Crossing Anomaly and Enhanced Tension with Reconstructed Scalar-Tensor Gravity
Dimitrios Efstratiou, Evangelos Achilleas Paraskevas, Leandros Perivolaropoulos
Recent cosmological data, including DESI DR2, highlight significant tensions within the CDM paradigm. When analyzed in the context of General Relativity (GR), the latest DESI da…
Large-scale peculiar velocities in the universe
Christos G. Tsagas, Leandros Perivolaropoulos, Kerkyra Asvesta
Observations have repeatedly confirmed the presence of large-scale peculiar motions in the universe, commonly referred to as ``bulk flows''. These are vast regions of the observabl…
BAO miscalibration cannot rescue late-time solutions to the Hubble tension
Davide Pedrotti, Luis A. Escamilla, Valerio Marra +2
Baryon Acoustic Oscillation (BAO) measurements play a key role in ruling out post-recombination solutions to the Hubble tension. However, because the data compression leading to th…
Hubble Tension and the G-step Model: Re-examination of Recent Constraints on Modified Local Physics
Leandros Perivolaropoulos, Ruchika
We critically examine recent claims challenging the viability of the G-step model (GSM) as a solution to the Hubble tension. The GSM proposes a 4 % increase in the effective…
Probing the Universe's Topology through a Quantum System?
Evangelos Achilleas Paraskevas, Leandros Perivolaropoulos
The global topology of the Universe could, in principle, affect quantum systems through boundary condition constraints. We investigate this connection by analyzing how compact, fla…
Dynamical dark energy with AdS-dS transitions vs. Baryon Acoustic Oscillations at 2.3-2.4
Özgür Akarsu, Maxim Eingorn, Leandros Perivolaropoulos +2
In this paper, written in memory of Alexei Starobinsky, we discuss the observational viability of the Ph-CDM model - a dynamical dark energy scenario based on a phantom…
Multi-Parameter Transitions in Cosmological Calibrators: A Resolution to the Hubble Tension from SH0ES Data Analysis
Mohit K. Sharma
The Hubble tension, characterized by discrepant measurements of the Hubble constant from early and late universe probes, remains one of the most significant challenges in cosmology…
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.…
Metastable Cosmological Constant and Gravitational Bubbles: Ultra-Late-Time Transitions in Modified Gravity
Dimitrios Efstratiou, Leandros Perivolaropoulos
The observed cosmological constant may originate as the minimum value of a scalar field potential, where the scalar field is frozen due to a large mass. If this vacuum is…
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…
Gravitational Wave Signatures Induced by Dark Fluid Accretion in Binary Systems
Evangelos Achilleas Paraskevas, Leandros Perivolaropoulos
We investigate the impact of dark fluid accretion on gravitational waveforms emitted by a compact binary system consisting of a supermassive black hole and a stellar-mass black hol…
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…