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We propose a nonlocal scalar-tensor model of gravity with pseudodifferential operators inspired by the effective action of p-adic string and string field theory on flat spacetime. An infinite number of derivatives act both on the metric and…

High Energy Physics - Theory · Physics 2010-12-28 Gianluca Calcagni , Giuseppe Nardelli

We consider some cosmological aspects of nonlocal modified gravity with $\Lambda$ term, where nonlocality is of the type $R \mathcal{F}(\Box) R$. Using ansatz of the form $\Box R = r R +s,$ we find a few a(t) nonsingular bounce cosmological…

General Relativity and Quantum Cosmology · Physics 2015-08-20 I. Dimitrijevic , B. Dragovich , J. Grujic , Z. Rakic

A non-local modified gravity model with an analytic function of the d'Alembert operator is considered. This model has been recently proposed as a possible way of resolving the singularities problem in cosmology. We present an exact bouncing…

High Energy Physics - Theory · Physics 2012-09-18 Alexey S. Koshelev , Sergey Yu. Vernov

We discuss some main aspects of theories of gravity containing non-local terms in view of cosmological applications. In particular, we consider various extensions of General Relativity based on geometrical invariants as $f(R, \Box^{-1} R)$,…

General Relativity and Quantum Cosmology · Physics 2022-01-13 Salvatore Capozziello , Francesco Bajardi

In this work, we analyzed the improved Deser-Woodard non-local gravity over the background of five different bouncing cosmologies, whose premise is avoid the initial singular state of the universe. We developed the numerical solution for…

General Relativity and Quantum Cosmology · Physics 2022-06-01 D. Jackson , R. Bufalo

Recently, evidence has been collected that a class of gravitational theories with certain non-local operators is renormalizable. We consider one such model which, at the linear perturbative level, reproduces the effective non-local action…

General Relativity and Quantum Cosmology · Physics 2014-08-26 Gianluca Calcagni , Leonardo Modesto , Piero Nicolini

One of the greatest problems of standard cosmology is the Big Bang singularity. Previously it has been shown that non-local ghostfree higher-derivative modifications of Einstein gravity in the ultra-violet regime can admit non-singular…

High Energy Physics - Theory · Physics 2010-12-03 Tirthabir Biswas , Tomi Koivisto , Anupam Mazumdar

We study accelerating cosmological solutions of a general class of non-linear gravities which depend on Gauss-Bonnet and other higher derivative invariants. To achieve this goal a local formulation with auxiliary scalars for arbitrary…

High Energy Physics - Theory · Physics 2009-01-16 Salvatore Capozziello , Emilio Elizalde , Shin'ichi Nojiri , Sergei D. Odintsov

We consider nonlocal modification of the Einstein theory of gravity in framework of the pseudo-Riemannian geometry. The nonlocal term has the form $\mathcal{H}(R) \mathcal{F}(\Box)\mathcal {G}(R)$, where $\mathcal{H}$ and $\mathcal{G}$ are…

High Energy Physics - Theory · Physics 2015-08-25 Ivan Dimitrijevic , Branko Dragovich , Jelena Grujic , Zoran Rakic

We study a particular exact solution to the Born-Infeld determinantal gravity consisting of a cosmological model which undergoes a brusque bounce. The latter consists of an event characterized by a non-null (but finite) value of the squared…

General Relativity and Quantum Cosmology · Physics 2016-07-20 Franco Fiorini

Non-local theories of gravity are considered extended theories of gravity, meaning that when the non-local terms are canceled out, the limit of General Relativity (GR) is obtained. Several reasons have led us to consider this theory with…

General Relativity and Quantum Cosmology · Physics 2023-12-06 Amodio Carleo

The accelerated expansion of the universe poses a significant challenge to General Relativity. Non-local modifications to gravity have emerged as a compelling class of theories to address this dark energy puzzle. Building upon earlier…

General Relativity and Quantum Cosmology · Physics 2025-11-19 Susobhan Mandal , S. Shankaranarayanan

This is a first study of the cosmology of classical fractional gravity, a nonlocal proposal endowed with self-adjoint fractional d'Alembertian operators which serves as the basis for an ultraviolet-complete theory of quantum gravity. We…

General Relativity and Quantum Cosmology · Physics 2026-05-01 Iván Salvador-García , Gianluca Calcagni

Despite many nice properties and numerous achievements, general relativity is not a complete theory. One of actual approaches towards more complete theory of gravity is its nonlocal modification. We present here a brief review of nonlocal…

General Relativity and Quantum Cosmology · Physics 2017-01-04 Branko Dragovich

We study exact solutions of the infinite derivative gravity with null radiation which belong to the class of almost universal Weyl type III/N Kundt spacetimes. This class is defined by the property that all rank-2 tensors ${B_{ab}}$…

General Relativity and Quantum Cosmology · Physics 2021-07-07 Ivan Kolář , Tomáš Málek , Anupam Mazumdar

This article aims to transform the infinite-order Lagrangian density for ghost-free infinite-derivative linearized gravity into non-local. To achieve it, we use the theory of generalized functions and the Fourier transform in the space of…

General Relativity and Quantum Cosmology · Physics 2022-03-30 Carlos Heredia , Ivan Kolář , Josep Llosa , Francisco José Maldonado Torralba , Anupam Mazumdar

In this paper we will show all the linearized curvature tensors in the infinite derivative ghost and singularity free theory of gravity in the static limit. We have found that in the region of non-locality, in the ultraviolet regime (at…

General Relativity and Quantum Cosmology · Physics 2018-10-03 Luca Buoninfante , Alexey S. Koshelev , Gaetano Lambiase , Anupam Mazumdar

We prove the equivalence between non-local gravity with an arbitrary form factor and a non-local gravitational system with an extra rank-2 symmetric tensor. Thanks to this reformulation, we use the diffusion-equation method to transform the…

High Energy Physics - Theory · Physics 2021-02-09 Gianluca Calcagni , Leonardo Modesto , Giuseppe Nardelli

A nonlocal gravity model (2.1) was introduced and considered recently [49], and two exact cosmological solutions in flat space were presented. The first solution is related to some radiation effects generated by nonlocal dynamics on dark…

General Relativity and Quantum Cosmology · Physics 2022-01-07 Ivan Dimitrijevic , Branko Dragovich , Zoran Rakic , Jelena Stankovic

In this manuscript we will present the theoretical framework of the recently proposed infinite derivative theory of gravity with a non-symmetric connection. We will explicitly derive the field equations at the linear level and obtain new…

General Relativity and Quantum Cosmology · Physics 2019-11-21 Álvaro de la Cruz-Dombriz , Francisco José Maldonado Torralba , Anupam Mazumdar
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