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f(T,B) gravity in a Friedmann–Lemaître–Robertson–Walker universe with nonzero spatial curvature

Mathematical Methods in the Applied Sciences, Volume 46, Issue 4, Page 3905-3922, 15 March 2023., 2023
We investigate exact solutions and the asymptotic dynamics for the Friedmann–Lemaître–Robertson–Walker universe with nonzero spatial curvature in the fourth‐order modified teleparallel gravitational theory known as f(T,B)$$ f\left(T,B\right) $$ theory. We show that the field equations admit a minisuperspace description, and they can reproduce any exact
Andronikos Paliathanasis, Genly Leon
wiley   +1 more source

How Extra Symmetries Affect Solutions in General Relativity

Universe, 2020
To get exact solutions to Einstein’s field equations in general relativity, one has to impose some symmetry requirements. Otherwise, the equations are too difficult to solve.
Aroonkumar Beesham, Fisokuhle Makhanya
doaj   +1 more source

Note on the Corrected Hawking Temperature of a Parametric Deformed Black Hole with Influence of Quantum Gravity

Advances in High Energy Physics, Volume 2023, Issue 1, 2023., 2023
In this paper, using the Hamilton‐Jacobi method, we discuss the tunnelling of fermions when the dual influence of quantum gravity and the deformation of a parameterized black hole are taken into account. With the influence of the generalized uncertainty principle, there exists an offset around the standard Hawking temperature.
Zhonghua Li, Mariana Frank
wiley   +1 more source

On the initial singularity in Kantowski–Sachs spacetime

European Physical Journal C: Particles and Fields, 2021
The emergent universe scenario is a proposal for resolving the Big Bang singularity problem in the standard Friedmann–Lemaitre–Robertson–Walker cosmology. In the context of this scenario, the Universe originates from a nonsingular static state.
Elham Ghorani, Yaghoub Heydarzade
doaj   +1 more source

Critical exponent of Fujita type for semilinear wave equations in Friedmann–Lemaître–Robertson–Walker spacetime

Mathematical methods in the applied sciences, 2021
We consider the nonlinear massless wave equation belonging to some family of the Friedmann–Lemaître–Robertson–Walker (FLRW) spacetime. We prove the global in time small data solutions for supercritical powers in the case of decelerating expansion ...
M. Ebert, Jorge Marques
semanticscholar   +1 more source

Density Perturbation and Cosmological Evolution in the Presence of Magnetic Field in f(R) Gravity Models

Advances in High Energy Physics, Volume 2022, Issue 1, 2022., 2022
In this paper, we have investigated the density perturbations and cosmological evolution in the FLRW universe in the presence of a cosmic magnetic field, which may be assumed to mimic primordial magnetic fields. Such magnetic fields have sufficient strength to influence galaxy formation and cluster dynamics, thereby leaving an imprint on the CMB ...
Samarjit Chakraborty, Sarbari Guha, Cesar A. Vasconcellos   +2 more
wiley   +1 more source

Thermodynamics of the FLRW apparent horizon

Physics Letters B, 2023
To investigate the relationship between gravity and thermodynamics in the case of dynamic systems, we interpret the apparent horizon of the Friedmann-Lemaître-Robertson-Walker (FLRW) spacetime as a thermodynamic system.
Luis M. Sánchez, Hernando Quevedo
doaj   +1 more source

Natural vacua in hyperbolic Friedmann-Robertson-Walker spacetimes [PDF]

Physical Review D, 1999
Recent evidence indicates that the Universe is open, i.e., spatially hyperbolic, longstanding theoretical preferences to the contrary notwithstanding. This makes it possible to select a vacuum state, Fock space, and particle definition for a quantized field, by requiring concordance with ordinary flat-spacetime theory at late times. The particle-number
openaire   +2 more sources

A Possible Solution of the Cosmological Constant Problem Based on GW170817 and Planck Observations with Minimal Length Uncertainty

Advances in High Energy Physics, Volume 2022, Issue 1, 2022., 2022
We propose generalized uncertainty principle (GUP) with an additional term of quadratic momentum motivated by string theory and black hole physics and providing a quantum mechanical framework for the minimal length uncertainty, at the Planck scale.
Abdel Magied Diab, Abdel Nasser Tawfik, Samir Iraoui   +2 more
wiley   +1 more source

A new solution for a generalized cosmological wormhole

European Physical Journal C: Particles and Fields, 2023
We find a new exact solution to Einstein field equations that represents a cosmological wormhole embedded in a flat Friedmann–Lemaître–Robertson–Walker universe. The new metric is a generalization of a previous cosmological wormhole solution found by Kim.
Daniela Pérez, Mário Raia Neto
doaj   +1 more source