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We present the idea that replacing the cosmological constant $\Lambda$ in the $\Lambda$CDM model by a distribution of walls, with very low tension compared to what one would expect from new physics, could help explaining the tension in the…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-13 Colin D. Froggatt , Holger Bech Nielsen

We investigate the observational viability of a quadratic dark energy expansion (QDEE) model as a phenomenological extension of the standard $\Lambda\mathrm{CDM}$ cosmological framework. This approach introduces the additional degrees of…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-21 Sehjal Khandelwal , Abraão J. S. Capistrano , Suresh Kumar , Rafael C. Nunes

We study cosmic evolution based on the fixed points in the dynamical analysis of the Degenerate Higher-Order Scalar-Tensor (DHOST) theories. We consider the DHOST theory in which the propagation speed of gravitational waves is equal to the…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-10 Wittaya Thipaksorn , Khamphee Karwan

Phantom energy which violates the dominant-energy condition and is not excluded by current constraints on the equation of state may be dominating the evolution of the universe now. It has been pointed out that in such a case the fate of the…

Astrophysics · Physics 2009-11-07 Pedro F. Gonzalez-Diaz

In this paper, we investigate the validity of the generalized second law of thermodynamics (GSLT) in the DGP brane world when universe is filled with interacting two fluid system: one in the form of cold dark matter and other is holographic…

General Relativity and Quantum Cosmology · Physics 2015-05-11 Jibitesh Dutta , Subenoy Chakraborty

It was first observed at the end of the last century that the universe is presently accelerating. Ever since, there have been several attempts to explain this observation theoretically. There are two possible approaches. The more…

High Energy Physics - Phenomenology · Physics 2020-04-14 Prasenjit Paul , Rikpratik Sengupta

Understanding the evolution of dark energy poses a significant challenge in modern cosmology, as it is responsible for the universe's accelerated expansion. In this study, we focus on a specific $f(T)$ cosmological model and analyze its…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 A. Zhadyranova , M. Koussour , S. Bekkhozhayev , V. Zhumabekova , J. Rayimbaev

We investigate the cosmological evolution of an interacting phantom energy model in which the phantom field has interaction with the dark matter. We discuss the existence and stability of scaling solutions for two types of specific…

Astrophysics · Physics 2007-05-23 Zong-Kuan Guo , Rong-Gen Cai , Yuan-Zhong Zhang

Horava gravity has been proposed as a renormalizable, higher-derivative, Lorentz-violating quantum gravity model without ghost problems. A Horava gravity based dark energy (HDE) model for dynamical dark energy has been also proposed earlier…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Eleonora Di Valentino , Nils A. Nilsson , Mu-In Park

In this paper, we investigate the possibility that a geometric model of dark energy that assume \textquotedblleft lower dimensions\textquotedblright, could generates a repulsive pressure which cause the current accelerated expansion of the…

General Relativity and Quantum Cosmology · Physics 2012-06-26 Miguel A. Garcia-Aspeitia

The new agegraphic Dark Energy (NADE) model (based on generalized uncertainty principle) interacting with Dark Matter (DM) is considered in this study via power-law form of the scale factor $a(t)$. The equation of state (EoS) parameter…

General Physics · Physics 2013-11-14 Antonio Pasqua , Surajit Chattopadhyay , Iuliia Khomenko

In this paper we have considered the holographic dark energy and studied it's cosmology and thermodynamics. We have analysed the generalized second law (GSL) of thermodynamics in a flat universe consists of interacting dark energy and dark…

General Relativity and Quantum Cosmology · Physics 2014-02-03 Praseetha P. , Titus K. Mathew

In this dissertation, the nature of Dark Energy (DE) is examined from both theoretical and phenomenological perspectives. The possibility of DE being a dynamic quantity in quantum field theory (QFT) in curved spacetime is studied. The…

General Relativity and Quantum Cosmology · Physics 2023-11-14 Cristian Moreno-Pulido

We investigate the unified first law and the generalized second law in a modified holographic dark energy model. The thermodynamical analysis on the apparent horizon can work and the corresponding entropy formula is extracted from the…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Hui Li , Yi Zhang

We outline a dynamical dark energy scenario whose signatures may be simultaneously tested by astronomical observations and laboratory experiments. The dark energy is a field with slightly sub-gravitational couplings to matter, a logarithmic…

Astrophysics · Physics 2009-06-23 Nemanja Kaloper

Differences in the values of the Hubble constant obtained from the local universe and the early universe have resulted in a significant tension. This tension signifies that our understanding of cosmology (physical processes and/or…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-22 Gawain Simpson , Krzysztof Bolejko , Stephen Walters

In this work, we investigate a cosmological scenario with a time-dependent cosmological constant $\Lambda$(t) within the spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) framework. Here we study a power-law $\Lambda(t)$CDM model…

General Relativity and Quantum Cosmology · Physics 2025-10-28 Archana Dixit , Manish Yadav , Anirudh Pradhan , M. S. Barak

In this work, we have carried on dynamical system analysis of hessence field coupling with dark matter in $f(T)$ gravity. We have analysed the critical points due to autonomous system. The resulting autonomous system is non-linear. So, we…

General Relativity and Quantum Cosmology · Physics 2017-07-20 Jyotirmay Das Mandal , Ujjal Debnath

In this letter, dark energy is obtained using dual roles of the Ricci scalar (as a physical field as well as geometry). Dark energy density, obtained here, mimics phantom and the derived Friedmann equation contains a term $\rho^2_{\rm de}/2…

High Energy Physics - Theory · Physics 2008-11-26 S. K. Srivastava

We investigate the interplay between varying electron mass ($m_e$) and dynamical dark energy by analysing the Chevallier-Polarski-Linder (CPL) parametrization and its non-crossing variants, both with and without a varying-$m_e$ component.…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-22 Adam Smith , Emre Özülker , Eleonora Di Valentino , Carsten van de Bruck