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Related papers: Einstein static universe from GUP

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We derive here the metric for Einstein's static universe (ESU) directly from Einstein equation, i.e., by considering both $G_{ik}$ and $T_{ik}$. We find that in order that the fluid pressure and acceleration are {\em uniform} and finite…

General Physics · Physics 2008-08-19 Abhas Mitra

We analyze the dynamics of a homogeneous and isotropic universe in the Einstein$--$Cartan theory of gravity. The coupling between the spin and torsion prevents gravitational singularities and replaces the Big Bang with a nonsingular big…

General Relativity and Quantum Cosmology · Physics 2019-03-05 Gabriel Unger , Nikodem Popławski

Based on an earlier introduced new class of generalized gravity-matter models defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the space-time manifold, we…

High Energy Physics - Theory · Physics 2016-11-29 Eduardo Guendelman , Ramon Herrera , Pedro Labrana , Emil Nissimov , Svetlana Pacheva

We consider the Einstein static and the de Sitter universe solutions and examine their instabilities in a subclass of quadratic modified theories for gravity. This modification proposed by Nash is an attempt to generalize general…

General Physics · Physics 2021-04-01 Mudhahir Al Ajmi

We investigate the time evolution of a homogeneous isotropic universe which consists of a perfect gas governed by the Einstein-Euler-de Sitter equations. Under suitable assumptions on the equation of state and assumptions on the present…

Analysis of PDEs · Mathematics 2015-11-23 Tetu Makino

The fundamental physical description of the Universe is based on two theories: Quantum Mechanics and General Relativity. Unified theory of Quantum Gravity (QG) is an open problem. Quantum Gravity Phenomenology (QGP) studies QG effects in…

General Relativity and Quantum Cosmology · Physics 2021-08-11 Vasil Todorinov

Based on the doubly special relativity we find a new type of generalized uncertainty principle (GUP) where the coordinate remain unaltered at the high energy while the momentum is deformed at the high energy so that it may be bounded from…

General Relativity and Quantum Cosmology · Physics 2018-09-26 Won Sang Chung , Hassan Hassanabadi

A link between the semiclassical Einstein equation and a maximal vacuum entanglement hypothesis is established. The hypothesis asserts that entanglement entropy in small geodesic balls is maximized at fixed volume in a locally maximally…

General Relativity and Quantum Cosmology · Physics 2016-06-28 Ted Jacobson

We prove global stability of Minkowski space for the Einstein vacuum equations in harmonic (wave) coordinate gauge for the set of restricted data coinciding with Schwartzschild solution in the neighborhood of space-like infinity. The result…

Analysis of PDEs · Mathematics 2011-04-21 Hans Lindblad , Igor Rodnianski

From the axiom of the unrestricted repeatability of all experiments, Bondi and Gold argued that the universe is in a stable, self-perpetuating equilibrium state. This concept generalizes the usual cosmological principle to the perfect…

Astrophysics · Physics 2007-05-23 Thomas B. Andrews

We study the stability of the isotropic vacuum Friedmann universe in gravity theories with higher-order curvature terms of the form $(R_{ab}R^{ab})^{n}$ added to the Einstein-Hilbert Lagrangian of general relativity on approach to an…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Jonathan Middleton , John D. Barrow

We investigate the effective dynamics of a spatially flat FLRW universe coupled to a massless scalar field by applying the improved generalized uncertainty principle (GUP)-inspired deformations to the algebra of Ashtekar-Barbero variables.…

General Relativity and Quantum Cosmology · Physics 2026-04-09 Saeed Rastgoo , Wilfredo Yupanqui

We investigate gravitational collapse of thick shell of fluid in the isotropic homogeneous universe without radiation described by the Einstein gravity with cosmological constant. We construct analytic solutions of this kind interpolating…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Shuichi Yokoyama

In this paper, we investigate the effects of a new version of the generalized uncertainty principle (modified GUP) on the dynamics of the Universe. As the modified GUP will modify the relation between the entropy and area of the apparent…

General Relativity and Quantum Cosmology · Physics 2017-02-22 Maha Salah , Fayçal Hammad , Mir Faizal , Ahmed Farag Ali

The emergent universe provides a possible method to avoid the big bang singularity by considering that the universe stems from an stable Einstein static universe rather than the singularity. Since the Einstein static universe exists before…

General Relativity and Quantum Cosmology · Physics 2023-05-11 Qihong Huang , Kaituo Zhang , He Huang , Bing Xu , Feiquan Tu

In addition to the second-order Einstein equations on four-dimensional homogeneous isotropic background universe filled with the single perfect fluid, we also derived the second-order perturbations of the continuity equation and the Euler…

General Relativity and Quantum Cosmology · Physics 2009-01-27 Kouji Nakamura

We study self-consistent static solutions for an Einstein universe in a graph-based induced gravity. The one-loop quantum action is computed at finite temperature. In particular, we demonstrate specific results for the models based on cycle…

General Relativity and Quantum Cosmology · Physics 2009-08-11 Nahomi Kan , Kiyoshi Shiraishi

The non-perturbative renormalisation of quantum gravity is investigated allowing for the metric to be reparameterised along the RG flow, such that only the essential couplings constants are renormalised. This allows us to identify a…

High Energy Physics - Theory · Physics 2021-08-11 Alessio Baldazzi , Kevin Falls

The Generalized Uncertainty Principle (GUP) naturally emerges in several quantum gravity models, predicting the existence of a minimal length at Planck scale. Here, we consider the quadratic GUP as a semiclassical approach to thermodynamic…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-25 Giuseppe Gaetano Luciano

We present the coherent states of the harmonic oscillator in the framework of the generalized (gravitational) uncertainty principle (GUP). This form of GUP is consistent with various theories of quantum gravity such as string theory, loop…

High Energy Physics - Theory · Physics 2013-03-04 Pouria Pedram