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We propose a new UV-complete dark energy model which is \underbar{\it neither} a cosmological constant nor a slowly rolling scalar field. Our dark energy is the flux of a top form in a hidden sector gauge theory similar to QCD. The top form…

High Energy Physics - Theory · Physics 2025-06-06 Nemanja Kaloper

We examine the validity of the $\Lambda$CDM model, and probe for the dynamics of dark energy using latest astronomical observations. Using the $Om(z)$ diagnosis, we find that different kinds of observational data are in tension within the…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-14 Yuecheng Zhang , Hanyu Zhang , Dandan Wang , Yanghan Qi , Yuting Wang , Gong-Bo Zhao

Constantly accumulating observational data continue to confirm that about 70% of the energy density today consists of dark energy responsible for the accelerated expansion of the Universe. We present recent observational bounds on dark…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-12 Shinji Tsujikawa

Dark energy is an elusive concept, which has been introduced two decades ago in order to make the acceleration of the universe a comprehensible phenomenon. However, the nature of this energy is far from being understood, both from a…

High Energy Physics - Phenomenology · Physics 2023-07-04 Miguel Hoyuelos , Pablo Sisterna

The suggestion that we occupy a privileged position near the centre of a large, nonlinear, and nearly spherical void has recently attracted much attention as an alternative to dark energy. Putting aside the philosophical problems with this…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-11 Adam Moss , James P. Zibin , Douglas Scott

Dark energy and dark matter are the dominant sources in the evolution of the late universe. They are currently only indirectly detected via their gravitational effects, and there could be a coupling between them without violating…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Christian G. Boehmer , Gabriela Caldera-Cabral , Ruth Lazkoz , Roy Maartens

We provide preliminary quantitative evidence that a new solution to averaging the observed inhomogeneous structure of matter in the universe [gr-qc/0702082, arxiv:0709.0732], may lead to an observationally viable cosmology without exotic…

Astrophysics · Physics 2008-11-26 Ben M. Leith , S. C. Cindy Ng , David L. Wiltshire

We develop here a relatively simple description of dark energy based on the dynamics of non-minimally coupled to gravity phantom scalar field which, in limit, corresponds to cosmological constant. The dark energy equation of state, obtained…

Astrophysics · Physics 2014-11-18 Aleksandra Kurek , Orest Hrycyna , Marek Szydlowski

The recent cosmological picture contains a significant tension indicating that our standard $\Lambda$CDM picture may be incomplete. Early Dark Energy models can alleviate the Hubble tension, by assuming an early acceleration that could…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-27 Teodora M. Matei , Cristian Croitoru , Tiberiu Harko

We investigate the clustering properties of dynamical dark energy using the latest cosmological observations. We describe the dark energy perturbation within two complementary frameworks, namely the Parameterized Post-Friedmann (PPF)…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-02 Yuhang Yang , Qingqing Wang , Xin Ren , Emmanuel N. Saridakis , Yi-Fu Cai

Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda; nowadays the concept is termed dark energy or quintessence. Physics also suggests the dark energy…

Astrophysics · Physics 2008-11-26 P. J. E. Peebles , Bharat Ratra

Cosmological parameters and dark energy (DE) behavior are generally constrained assuming \textit{a priori} models. We work out a model-independent reconstruction to bound the key cosmological quantities and the DE evolution. Through the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-22 Orlando Luongo , Marco Muccino

The coupled dark energy model provides a possible approach to mitigate the coincidence problem of cosmological standard model. Here, the coupling term is assumed as $\bar{Q}=3H\xi_x\bar{\rho}_x$, which is related to the interaction rate and…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-11 Weiqiang Yang , Hang Li , Yabo Wu , Jianbo Lu

We use the latest compilation of observational Hubble parameter measurements estimated with the differential evolution of cosmic chronometers, in combination with the local value of the Hubble constant recently measured with 2.4% precision,…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-13 Rafael C. Nunes , Supriya Pan , Emmanuel N. Saridakis

Understanding the nature of the dark energy is one of the most important task in cosmology. In principle several cosmological observations can be used to discriminate amid a static cosmological constant contribution and a dynamical…

Astrophysics · Physics 2007-05-23 P. S. Corasaniti

In view of late-time cosmic acceleration, a dark energy cosmological model is revisited wherein Einstein's cosmological constant is considered as a candidate of dark energy. Exact solution of Einstein field equations (EFEs) is derived in a…

General Relativity and Quantum Cosmology · Physics 2019-11-22 S. K. J. Pacif , Md Salahuddin Khan , L. K. Paikroy , Shalini Singh

In this article we compare a variety of well known dynamical dark energy models using the cosmic microwave background measurements from the 2018 Planck legacy and 2015 Planck data releases, the baryon acoustic oscillations measurements and…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-07 Weiqiang Yang , Eleonora Di Valentino , Supriya Pan , Yabo Wu , Jianbo Lu

Constraints on a dark energy dominated Universe are obtained from an interplay between Bayesian Machine Learning and string Swampland criteria. The approach here differs from previous studies, since in the generative process Swampland…

General Relativity and Quantum Cosmology · Physics 2021-05-05 Emilio Elizalde , Martiros Khurshudyan

In a recent paper \cite{Artymowski:2020zwy} we suggested the possibility that the present acceleration of the Universe is due to thermodynamical behavior of unparticles. The model is free of scalar fields, modified gravity, a Cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-19 Michał Artymowski , Ido Ben-Dayan , Utkarsh Kumar

The $\Lambda$ cold dark matter ($\Lambda$CDM) cosmological model provides a good description of a wide range of astrophysical and cosmological observations. However, severe challenges to the phenomenological $\Lambda$CDM model have emerged…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-10 X. D. Jia , J. P. Hu , D. H. Gao , S. X. Yi , F. Y. Wang