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Related papers: Light bending by the cosmological constant

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In this paper we present a statistical description of the cosmological constant in terms of massless bosons (gravitons). To this purpose, we use our recent results implying a non vanishing temperature ${T_{\Lambda}}$ for the cosmological…

High Energy Physics - Theory · Physics 2016-06-30 Stefano Viaggiu

We study the evolution of the cosmic-mass-density contrast beyond the Robertson-Walker geometry including the small contribution of acceleration. We derive a second-order evolution equation for the density contrast within the spherical…

Astrophysics · Physics 2009-11-10 D. Palle

We assume a one-to-one correspondence between comoving coordinates and the cosmic rest frame in a spherically symmetric inhomogeneous universe. This strongly restricts the solutions of Einstein's equations: (i) The pressure must be zero.…

General Physics · Physics 2018-05-29 Günter Scharf

Einsteins gravity with a cosmological constant $\Lambda$ in four dimensions can be reformulated as a $\lambda \phi^4$ theory characterized solely by the dimensionless coupling $\lambda \propto G_N \Lambda$ ($G_N$ being Newton's constant).…

High Energy Physics - Phenomenology · Physics 2025-10-09 Mathew Thomas Arun , Nabeel Thahir

The tensions between the values of Hubble constant obtained from the early and the late Universe data pose a significant challenge to modern cosmology. Possible modifications of the flat homogeneous isotropic cosmological {\Lambda}CDM model…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-14 S. L. Parnovsky

In this paper we suppose that the cosmological constant will change when the universe expends. For a general consideration, the cosmological constant is assumed to be a function of scale factor and Hubble constant. According to the ADM…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-03 Jin-Zhang Tang , Qiang Xu

The gravitational lens equation resulting from a single (non-linear) mass concentration (the main lens) plus inhomogeneities of the large-scale structure is shown to be strictly equivalent to the single-plane gravitational lens equation…

Astrophysics · Physics 2015-06-24 Peter Schneider

The flatness and cosmological constant problems are solved with varying speed of light c, gravitational coupling strength G and cosmological parameter Lambda, by explicitly assuming energy conservation of observed matter. The present…

General Relativity and Quantum Cosmology · Physics 2009-10-31 P. Gopakumar , G. V. Vijayagovindan

We build a minimal extension of General Relativity in which Newton's gravitational coupling, $G$, the speed of light, $c$, and the cosmological constant, $\Lambda$, are spacetime variables. This is done while satisfying the contracted…

General Relativity and Quantum Cosmology · Physics 2017-04-27 Guilherme Franzmann

In this paper we provide both a diagnosis and resolution of the cosmological constant problem, one in which a large (as opposed to a small) cosmological constant $\Lambda$ can be made compatible with observation. We trace the origin of the…

Astrophysics · Physics 2009-10-31 Philip D. Mannheim

Recent cosmological observations suggest the existence of a positive cosmological constant $\Lambda$ with the magnitude $\Lambda(G\hbar/c^3) \approx 10^{-123}$. This review discusses several aspects of the cosmological constant both from…

High Energy Physics - Theory · Physics 2008-11-26 T. Padmanabhan

We present a new solution to the cosmological constant (CC) and coincidence problems in which the observed value of the CC, $\Lambda$, is linked to other observable properties of the universe. This is achieved by promoting the CC from a…

General Relativity and Quantum Cosmology · Physics 2015-03-17 Douglas J. Shaw , John D. Barrow

We present new limits on cosmological parameters from the statistics of gravitational lensing, based on the recently revised knowledge of the luminosity function and internal dynamics of E/S0 galaxies that are essential in lensing…

Astrophysics · Physics 2009-10-30 Masashi Chiba , Yuzuru Yoshii

We consider a model of non-local gravity with a large bare cosmological constant, $\Lambda$, and study its cosmological solutions. The model is characterized by a function $f(\psi)=f_0 e^{\alpha\psi}$ where $\psi=\Box^{-1}R$ and $\alpha$ is…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Ying-li Zhang , Misao Sasaki

Using the scalar and tensor virial equations, the Lane-Emden equation expressing the hydrostatic equilibrium and small oscillations around the equilibrium, we show how the cosmological constant $\Lambda$ affects various astrophysical…

Astrophysics · Physics 2009-11-13 A. Balaguera-Antolinez , M. Nowakowski

We analyze gravitational lensing in a matched Kottler spacetime with cosmological constant $\Lambda$, where a uniform-density fluid sphere described by the interior Kottler solution is smoothly joined to the exterior Kottler region. We…

General Relativity and Quantum Cosmology · Physics 2026-05-29 Mourad Guenouche

Strong gravitational lensing has traditionally been one of the few phenomena said to oppose a large cosmological constant; many analyses of lens statistics have given upper limits on $\Omega_\Lambda$ that are marginally inconsistent with…

Astrophysics · Physics 2009-11-07 Charles R. Keeton

The standard model of cosmology is based on the hypothesis that the Universe is spatially homogeneous and isotropic. When interpreting most observations, this cosmological principle is applied stricto sensu: the light emitted by distant…

General Relativity and Quantum Cosmology · Physics 2024-01-15 Pierre Fleury

We provide a new perspective on the cosmological constant by exploring the background-independent Wheeler-DeWitt quantization of general relativity. The Chern-Simons-Kodama state of quantum gravity, a generalization of the Hartle-Hawking…

General Relativity and Quantum Cosmology · Physics 2025-06-19 Stephon Alexander , Heliudson Bernardo , Aaron Hui

We formulate the basic framework of thermodynamical entropic force cosmology which allows variation of the gravitational constant $G$ and the speed of light $c$. Three different approaches to the formulation of the field equations are…

High Energy Physics - Theory · Physics 2016-03-10 Mariusz P. Dabrowski , H. Gohar , Vincenzo Salzano
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