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The quest for understanding the late-time acceleration is haunted by an immense freedom in the analysis of dynamical models for dark energy in extended parameter spaces. Often-times having no prior knowledge at our disposal, arbitrary…

宇宙学与河外天体物理 · 物理学 2019-02-12 Federico Tosone , Balakrishna S. Haridasu , Vladimir V. Luković , Nicola Vittorio

We constrain f_nu = Omega_nu / Omega_m, the fractional contribution of neutrinos to the total mass density in the Universe, by comparing the power spectrum of fluctuations derived from the 2dF Galaxy Redshift Survey with power spectra for…

Over the last decades, tests on the standard model of cosmology, the so-called $\Lambda$CDM model, have been widely analysed and compared with many different models for describing dark energy. Modified gravities have played an important…

广义相对论与量子宇宙学 · 物理学 2024-12-13 Sergei D. Odintsov , Diego Sáez-Chillón Gómez , German S. Sharov

We present an effective field theory (EFT) approach to extract fundamental cosmological parameters from the Lyman-alpha forest flux fluctuations as an alternative to the standard simulation-based techniques. As a first application, we…

宇宙学与河外天体物理 · 物理学 2025-02-21 Mikhail M. Ivanov , Michael W. Toomey , Naim Göksel Karaçaylı

Constraints on the original Cardassian model and the modified polytropic Cardassian model are examined from the latest derived 397 Type Ia supernova (SNe Ia) data, the size of baryonic acoustic oscillation peak from the Sloan Digital Sky…

宇宙学与河外天体物理 · 物理学 2015-05-13 Tai-Shan Wang , Puxun Wu

This article discusses a dark energy cosmological model in the standard theory of gravity - general relativity with a broad scalar field as a source. Exact solutions of Einstein's field equations are derived by considering a particular form…

广义相对论与量子宇宙学 · 物理学 2022-08-23 S. K. J. Pacif , Simran Arora , P. K. Sahoo

Assuming a simple form for the growth index gamma(z) depending on two parameters gamma_0 = gamma(z=0) and gamma_1 = gamma'(z=0), we show that these parameters can be constrained using background expansion data. We explore systematically the…

宇宙学与河外天体物理 · 物理学 2018-10-31 Radouane Gannouji , David Polarski

We compute the Bayesian evidences for one- and two-parameter models of evolving dark energy, and compare them to the evidence for a cosmological constant, using current data from Type Ia supernova, baryon acoustic oscillations, and the…

天体物理学 · 物理学 2008-11-26 Andrew R Liddle , Pia Mukherjee , David Parkinson , Yun Wang

We propose a new fluid model of dark energy for $-1 \leq \omega_{\text{eff}} \leq 0$ as an alternative to the generalized Chaplygin gas models. The energy density of dark energy fluid is severely suppressed during barotropic matter dominant…

宇宙学与河外天体物理 · 物理学 2010-11-23 Hoavo Hova , Huanxiong Yang

Recent supernovae of type Ia measurements and other astronomical observations suggest that our universe is in accelerating phase of evolution at the present epoch. While a dark energy of unknown form is usually proposed as the most feasible…

天体物理学 · 物理学 2008-11-26 Andrzej Borowiec , Wlodzimierz Godlowski , Marek Szydlowski

We carry out an independent re-analysis of the Dark Energy Spectroscopic Instrument (DESI) public dataset, focusing on extensions to the standard cosmological model, $\Lambda$CDM. Utilizing the dataset and Effective Field Theory (EFT)-based…

宇宙学与河外天体物理 · 物理学 2026-04-15 Anton Chudaykin , Mikhail M. Ivanov , Oliver H. E. Philcox

We investigate Lyman-alpha forest flux statistics in mixed fuzzy dark matter (FDM) and cold dark matter (CDM) cosmologies using the Fluctuating Gunn-Peterson Approximation (FGPA) applied to hybrid Schr\"odinger-Poisson and N-body…

宇宙学与河外天体物理 · 物理学 2026-04-08 Yourong Frank Wang

We propose a phenomenological unified model for dark matter and dark energy based on an equation of state parameter $w$ that scales with the $\arctan$ of the redshift. The free parameters of the model are three constants: $\Omega_{b0}$,…

宇宙学与河外天体物理 · 物理学 2015-11-17 R. R. Cuzinatto , L. G. Medeiros , E. M. de Morais

The Generalized Uncertainty Principle (GUP) stands out as a nearly ubiquitous feature in quantum gravity modeling, predicting the emergence of a minimum length at the Planck scale. Recently, it has been shown to modify the area-law scaling…

广义相对论与量子宇宙学 · 物理学 2025-02-17 Giuseppe Gaetano Luciano , Yassine Sekhmani

An analysis of cosmological mixed dark matter models in spatially flat Friedmann Universe with zero $\Lambda$-term is presented. We argue that the introduction of cosmic gravity waves helps to satisfy observational constraints. The analysis…

天体物理学 · 物理学 2007-05-23 E. V. Mikheeva

The nature of dark matter is increasingly constrained by cosmological data. In this paper, we examine the implications of the Cosmic Microwave Background anisotropy limits on the density of cold dark matter under different theoretical…

天体物理学 · 物理学 2009-11-07 A. Melchiorri , J. Silk

The Effective Field Theory of Dark Energy (EFTofDE) provides a systematic and model-independent framework to study dark energy (DE) and modified gravity (MG) with one additional scalar degree of freedom. It can describe the known models…

宇宙学与河外天体物理 · 物理学 2025-09-18 Chi Zheng , Wei Liu , Zonghao Zhan , Wenjuan Fang

The new 182 gold supernova Ia data, the baryon acoustic oscillation measurement and the shift parameter determined from the Sloan Digital Sky Survey and the three-year Wilkinson Microwave Anisotropy Probe data are combined to reconstruct…

天体物理学 · 物理学 2008-11-26 Yungui Gong , Anzhong Wang

We study the coincidence problem of late cosmic acceleration by assuming that the present ratio between dark matter and dark energy is a slowly varying function of the scale factor. As dark energy component we consider two different…

天体物理学 · 物理学 2009-11-13 Sergio del campo , Ramon Herrera , Diego Pavon

We propose a revised cosmological scenario that extends the $\Lambda$ Cold Dark Matter ($\Lambda$CDM) framework by incorporating metric $f(R)$ gravity in the Jordan frame. In this model, the dark energy component arises from a non-minimally…

宇宙学与河外天体物理 · 物理学 2026-01-08 Giovanni Montani , Luis A. Escamilla , Nakia Carlevaro , Eleonora Di Valentino