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Discrepancies between distance measurements and $\Lambda$CDM predictions reveal notable features in the distance-redshift relation, possibly suggesting the presence of an evolving dark energy component. Given the central role of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-06 David Camarena , Kylar Greene , John Houghteling , Francis-Yan Cyr-Racine

The fundamental laws of physics are required to be invariant under local spatial scale change. In 3-dimensional space, this leads to a variation in Planck constant \hbar and speed of light c. They vary as \hbar ~ a^(1/2) and c ~ a^(-1/2), a…

General Physics · Physics 2013-02-28 Hoang K. Nguyen

We investigate the effect on cosmological evolution of a strongly coupled quantum field that undergoes renormalization group flow from a UV CFT to an IR CFT. The field theory is defined by perturbation of a holographic CFT by a relevant…

High Energy Physics - Theory · Physics 2025-08-12 Mark Van Raamsdonk , Rana Zibakhsh

The absence of an identified consequence at solar system scale of the cosmological space expansion is usually explained considering that space expansion does not affect local anysotropies in matter distribution. This can also be explained…

General Physics · Physics 2007-05-23 A. Gouveia Oliveira , Rodrigo de Abreu

We show that there is no need for the hypothetical Dark Energy (DE) and Dark Matter (DM) to explain phenomena attributed to them. In contrast to the consensus of the last decade, we show that the time derivative of the cosmological scale…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-15 Shlomo Barak , Elia M Leibowitz

The cosmological vacuum decay scenario recently proposed by Wang and Meng \cite{wm} is rediscussed. From thermodynamic arguments it is found that the $\epsilon$ parameter quantifying the vacuum decay rate must be positive in the presence of…

Astrophysics · Physics 2009-11-13 J. S. Alcaniz , J. A. S. Lima

We show that the presence of a temporal electromagnetic field on cosmological scales generates an effective cosmological constant which can account for the accelerated expansion of the universe. Primordial electromagnetic quantum…

Astrophysics · Physics 2011-07-13 Jose Beltran Jimenez , Antonio L. Maroto

A late epoch cosmic acceleration may be naturally entangled with cosmic coincidence -- the observation that at the onset of acceleration the vacuum energy density fraction nearly coincides with the matter density fraction. In this Letter we…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-07 Ciaran Doolin , Ishwaree P. Neupane

The perfect Planck spectrum of the observed cosmic microwave background radiation indicates that our universe must be in thermal equilibrium. The dark sector of the universe should also be in the same equilibrium state with dark matter and…

General Physics · Physics 2016-12-14 Ti-Pei Li , Mei Wu

We consider a multidimensional cosmological model with FRW type metric having 4-dimensional space-time and $d$-dimensional Ricci-flat internal space sectors with a higher dimensional cosmological constant. We study the classical cosmology…

General Relativity and Quantum Cosmology · Physics 2015-06-05 K. Zeynali , F. Darabi , H. Motavalli

A new speculative model for the expansion of our universe has been under development by the author for the last two decades, which correctly predicts astronomical measurements with no dark matter or dark energy. This new closed model (no…

General Physics · Physics 2010-02-16 Charles B. Leffert

The idea that the cosmological term, Lambda, should be a time dependent quantity in cosmology is a most natural one. It is difficult to conceive an expanding universe with a strictly constant vacuum energy density, namely one that has…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Joan Sola

We show that within the cosmology associated with conformal gravity the age of the universe is given as $1/H_0$, to thus overcome the current cosmological age crisis. We show that while the parameter $\Omega_{mat} = \rho_{mat} / \rho_C$…

Astrophysics · Physics 2007-05-23 Philip D. Mannheim

A new conjecture is proposed that there are two sorts of matter called s-matter and v-matter which are symmetric and whose gravitational masses are opposite to each other, although both masses are positive. Therefore, there are two sorts of…

General Physics · Physics 2011-03-09 Shi-Hao Chen

A conformal transformation of a static or stationary spacetime by a time dependent conformal scale factor ${S(\tau )}^2$ is one of the methods of producing a cosmological spacetime. Using this knowledge and Brans-Dicke (BD) field equations,…

General Relativity and Quantum Cosmology · Physics 2023-12-07 Dilek K. Çiftci , Ali Demirözlü

It has been widely believed that variability of the fine-structure constant alpha would imply detectable violations of the weak equivalence principle. This belief is not justified in general. It is put to rest here in the context of the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Jacob D. Bekenstein

The evolution of the wave function in quantum mechanics is deterministic like that of classical waves. Only when we bring in observers the fundamentally different quantum reality emerges. Similarly the introduction of observers changes the…

General Physics · Physics 2020-10-16 Jan O. Stenflo

We disclose the effects of an extra longitudinal degree of freedom on the evolution of perturbations in the framework of mimetic gravity. We consider a flat Friedmann-Robertson-Walker (FRW) background and explore the linear perturbations by…

General Relativity and Quantum Cosmology · Physics 2022-08-02 Bita Farsi , Ahmad Sheykhi

Cosmography can be considered as a sort of a model-independent approach to tackle the dark energy/modified gravity problem. In this review, the success and the shortcomings of the $\Lambda$CDM model, based on General Relativity and standard…

General Relativity and Quantum Cosmology · Physics 2019-04-09 Salvatore Capozziello , Rocco D'Agostino , Orlando Luongo

Context. Explaining the accelerated expansion of the Universe is one of the fundamental challenges in physics today. Cosmography provides information about the evolution of the universe derived from measured distances, assuming only that…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-05 Marek Demianski , Ester Piedipalumbo , Disha Sawant , Lorenzo Amati
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