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The study of physics at the Planck scale has garnered significant attention due to its implications for understanding the fundamental nature of the universe. At the Planck scale, quantum fluctuations challenge the classical notion of…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Weihu Ma , Yu-Gang Ma

It is very likely that the quantum description of spacetime is quite different from what we perceive at large scales, $l\gg (G\hbar/c^3)^{1/2}$. The long wave length description of spacetime, based on Einstein's equations, is similar to the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 T. Padmanabhan

In a geometrical approach to gravity the metric and the (gravitational) connection can be independent and one deals with metric-affine theories. We construct the most general action of metric-affine effective field theories, including a…

High Energy Physics - Theory · Physics 2022-12-16 Gianfranco Pradisi , Alberto Salvio

In this work we demonstrate that wormholes can in principle be naturally created during the cosmological bounce without the need for the exotic matter or any kind of additional modifications of the gravitational sector, apart from the one…

General Relativity and Quantum Cosmology · Physics 2025-02-07 Petar Pavlović , Marko Sossich

Motivated by hints of the effective emergent nature of spacetime structure, we formulate a spacetime-free algebraic framework for quantum theory, in which no a priori background geometric structure is required. Such a framework is necessary…

General Relativity and Quantum Cosmology · Physics 2017-01-25 Matti Raasakka

This review presents a comprehensive overview of Myrzakulov gravity, highlighting key developments and significant results shaping the theory. It examines the foundational principles, field equations, and the role of non-metricity and…

General Relativity and Quantum Cosmology · Physics 2025-04-04 Davood Momeni , Ratbay Myrzakulov

We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered…

General Relativity and Quantum Cosmology · Physics 2022-09-15 Marco de Cesare , Fedele Lizzi , Mairi Sakellariadou

First, the ideas introduced in the wormhole research field since the work of Morris and Thorne are briefly reviewed, namely, the issues of energy conditions, wormhole construction, stability, time machines and astrophysical signatures.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Jose' P. S. Lemos , Francisco S. N. Lobo , Sergio Quinet de Oliveira

In this paper, we use the embedding class-I technique to examine the effect of charge on traversable wormhole geometry in the context of $f(\mathcal{G})$ theory, where $\mathcal{G}$ is the Gauss-Bonnet term. For this purpose, we consider…

General Relativity and Quantum Cosmology · Physics 2024-03-04 M. Zeeshan Gul , M. Sharif

We consider the inhomogeneous Morris-Thorne wormhole metric with matter tensors characterised by a novel linear equation of state in $f(R)$ gravity. Using the Einstein's field equations in metric $f(R)$ gravity we model solutions for both…

General Relativity and Quantum Cosmology · Physics 2025-11-26 Subhasis Nalui , Subhra Bhattacharya

In this work, we find novel static and spherically symmetric wormhole geometries using a three-form field. By solving the gravitational field equations, we find a variety of analytical and numerical solutions and show that it is possible…

General Relativity and Quantum Cosmology · Physics 2018-08-10 Bruno J. Barros , Francisco S. N. Lobo

In this work, we explore the possibility that static and spherically symmetric traversable wormhole geometries are supported by modified teleparallel gravity or f(T) gravity, where T is the torsion scalar. Considering the field equations…

General Relativity and Quantum Cosmology · Physics 2012-02-16 Christian G. Boehmer , Tiberiu Harko , Francisco S. N. Lobo

Macroscopic traversable wormhole solutions to Einstein's field equations in $(2+1)$ and $(3+1)$ dimensions with a cosmological constant are investigated. Ensuring traversability severely constrains the material used to generate the…

General Relativity and Quantum Cosmology · Physics 2009-10-22 M. S. Delgaty , R. B. Mann

The purpose of this paper is to show that wormholes in noncommutative geometry can be macroscopic, based in part on an earlier study. The necessary violation of the weak energy condition is attributable to the noncommutative-geometry…

General Relativity and Quantum Cosmology · Physics 2013-12-25 Peter K. F. Kuhfittig

We study wormhole geometries embedded in an expanding universe within a four-scalar non-linear $\sigma$ model, where the target-space metric is identified with the spacetime Ricci tensor. In this framework, wormholes can remain stable even…

General Relativity and Quantum Cosmology · Physics 2026-01-16 Taishi Katsuragawa , Shin'ichi Nojiri , Sergei D. Odintsov

This paper discusses several new exact solutions of static wormholes in $f(R)$ gravity with a noncommutative-geometry background, which replaces point-like structures by smeared objects. In the first part of the paper we assume the…

General Relativity and Quantum Cosmology · Physics 2014-10-21 Mubasher Jamil , Farook Rahaman , Ratbay Myrzakulov , P. K. F. Kuhfittig , Nasr Ahmed , Umar F Mondal

In this work, we analyse the evolution of time-dependent traversable wormhole geometries in a Friedmann-Lema\^{i}tre-Robertson-Walker background in the context of the scalar-tensor representation of hybrid metric-Palatini gravity. We deduce…

General Relativity and Quantum Cosmology · Physics 2021-04-06 Mahdi Kord Zangeneh , Francisco S. N. Lobo

We construct a broad family of thin-shell wormholes with circular symmetry in (2+1)-dimensional F(R) theories of gravity, with constant scalar curvature R. We study the stability of the static configurations under perturbations preserving…

General Relativity and Quantum Cosmology · Physics 2021-08-05 Cecilia Bejarano , Ernesto F. Eiroa , Griselda Figueroa-Aguirre

In this work, we analyse static spherically symmetric solutions in the framework of mimetic gravity, an extension of general relativity where the conformal degree of freedom of gravity is isolated in a covariant fashion. Here we extend…

General Relativity and Quantum Cosmology · Physics 2018-12-13 Ratbay Myrzakulov , Lorenzo Sebastiani , Sunny Vagnozzi , Sergio Zerbini

The current study examines the geometry of static wormholes with anisotropic matter distribution in context of modified $f(\mathcal{G})$ gravity. We consider the well known Noether and conformal symmetries, which help in investigating…

General Relativity and Quantum Cosmology · Physics 2023-04-14 Tayyaba Naz , G. Mustafa , M. Farasat Shamir