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We discuss how to extract information about the cosmological constant from the Wheeler-DeWitt equation, considered as an eigenvalue of a Sturm-Liouville problem. A generalization to a f(R)theory is taken under examination. The equation is…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Remo Garattini

We investigate the Schwarzschild-(anti) de Sitter spacetime with the anisotropic metric ansatz. The Wheeler-DeWitt equation for such a metric is solved numerically. In the presence of the cosmological constant $\Lambda$, we show that two…

General Relativity and Quantum Cosmology · Physics 2023-08-09 Chen-Hsu Chien , Gansukh Tumurtushaa , Dong-han Yeom

The Abnormally Weighting Energy (AWE) hypothesis consists of assuming that the dark sector of cosmology violates the weak equivalence principle (WEP) on cosmological scales, which implies a violation of the strong equivalence principle for…

Astrophysics · Physics 2008-11-26 A. Fuzfa , J. -M. Alimi

We study the canonical quantization of the induced 2d-gravity and the pure gravity CGHS-model on a closed spatial section. The Wheeler-DeWitt equations are solved in (spatially homogeneous) choices of the internal time variable and the…

High Energy Physics - Theory · Physics 2008-11-26 J. Navarro-Salas , C. F. Talavera

We generalize the cosmic energy equation to the case when massive particles interact via a modified gravitational potential of the form phi(a, r), which is allowed to explicitly depend upon the cosmological time through the expansion factor…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-23 Yuri Shtanov , Varun Sahni

In this paper, we consider a quantum model of gravitation interacting with a Born-Infeld(B-I) type scalar field $\phi$. The corresponding Wheeler-Dewitt equation can be solved analytically for both very large and small cosmological scale…

High Energy Physics - Theory · Physics 2007-05-23 H. Q. Lu , Z. G. Huang , W. Fang , P. Y. Ji

In this work, a flat Friedmann-Robertson-Walker (FRW) universe with dust and a cosmological constant is quantized. By means of a canonical transformation, the classical Hamiltonian is reduced to that of either a harmonic oscillator or…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Edésio M. Barboza , Nivaldo A. Lemos

We present the data-driven reconstruction of gravitational theories and Dark Energy models on cosmological scales. We showcase the power of present cosmological probes at constraining these models and quantify the knowledge of their…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-22 Marco Raveri

Current observational data indicate that dark energy (DE) is a cosmological constant without considering its conclusiveness evidence. Considering the dynamic nature of $\Lambda$ individually as a function of time and the scale factor, we…

General Relativity and Quantum Cosmology · Physics 2023-11-07 Jafar Khodagholizadeh

We discuss how to extract information about the cosmological constant from the Wheeler-DeWitt equation, considered as an eigenvalue of a Sturm-Liouville problem in a generic spherically symmetric background. The equation is approximated to…

General Relativity and Quantum Cosmology · Physics 2015-05-19 Remo Garattini

The modified F(R)-scalar-Gauss-Bonnet gravity is proposed as dark energy model. The reconstruction program for such theory is developed. It is explicitly demonstrated that the known classical universe expansion history (deceleration epoch,…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov , Petr V. Tretyakov

Recently Horava proposed a renormalizable gravity theory with higher spatial derivatives in four dimensions which reduces to Einstein gravity with a non-vanishing cosmological constant in IR but with improved UV behaviors. Here, I consider…

High Energy Physics - Theory · Physics 2010-01-15 Mu-in Park

In this work the wave functions associated to the quantum relativistic universe, which is described by the Wheeler-DeWitt equation, are obtained. Taking into account different kinds of energy density, namely, matter, radiation, vacuum, dark…

General Relativity and Quantum Cosmology · Physics 2021-07-07 H. S. Vieira , V. B. Bezerra , C. R. Muniz , M. S. Cunha

We compute the Zero Point Energy in a spherically symmetric background combining the high energy distortion of Gravity's Rainbow with the modification induced by a f(R) theory. Here f(R) is a generic analytic function of the Ricci curvature…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Remo Garattini

The modified gravity, which eliminates the need for dark energy and which seems to be stable, is considered. The terms with positive powers of the curvature support the inflationary epoch while the terms with negative powers of the…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

In this article we present the cosmological equivalence between the relativistic Finsler-Randers cosmology, with dark energy and modified gravity constructions, at the background level. Starting from a small deviation from the quadraticity…

General Relativity and Quantum Cosmology · Physics 2013-12-17 Spyros Basilakos , Alexandros P. Kouretsis , Emmanuel N. Saridakis , Panayiotis Stavrinos

The cosmological constant induced by quantum fluctuation of the graviton on a given background is considered as a tool for building a spectrum of different geometries. In particular, we apply the method to the Schwarzschild background with…

General Relativity and Quantum Cosmology · Physics 2008-12-23 Remo Garattini

Here we show that, Eddington's pure affine gravity, when extended with Riemann curvature, leads to gravitational field equations that incorporate matter. This Riemanned Eddington gravity outfits a setup in which matter gravitates normally…

General Relativity and Quantum Cosmology · Physics 2014-09-16 Durmus A. Demir

We investigate the evolution of cosmological perturbations in models of dark energy described by a time-like unit normalized vector field specified by a general function $\mathcal{F}(\mathcal{K})$, so-called Generalized Einstein-Aether…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-04 Richard A. Battye , Francesco Pace , Damien Trinh

We apply the gravity-thermodynamics conjecture, namely the first law of thermodynamics on the Universe horizon, but using the generalized Kaniadakis entropy instead of the standard Bekenstein-Hawking one. The former is a one-parameter…

General Relativity and Quantum Cosmology · Physics 2021-12-07 Andreas Lymperis , Spyros Basilakos , Emmanuel N. Saridakis