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Loop quantum cosmology predicts that, in simple models, the big bang singularity of classical general relativity is replaced by a quantum bounce. Because of the extreme physical conditions near the bounce, a natural question is whether the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Alejandro Corichi , Parampreet Singh

In this work we shall explore the effects of non commutativity in fractional classical and quantum schemes using the flat Friedmmann-Robertson-Walker (FRW) cosmological model coupled to a scalar field in the K-essence formalism. In previous…

General Relativity and Quantum Cosmology · Physics 2024-03-04 J. Socorro , J. Juan Rosales , Leonel Toledo-Sesma

Nonlocal gravity has been shown to provide a phenomenologically viable infrared modification of GR. A natural question is whether the required nonlocality can emerge from perturbative quantum loop corrections due to light particles. We show…

High Energy Physics - Theory · Physics 2016-04-06 Michele Maggiore

Virtual massless particles in quantum loops lead to nonlocal effects which can have interesting consequences, for example, for primordial magnetogenesis in cosmology or for computing finite $N$ corrections in holography. We describe how the…

High Energy Physics - Theory · Physics 2018-07-04 Teresa Bautista , André Benevides , Atish Dabholkar

General relativity allows a variety of future singularities to occur in the evolution of the universe. At these future singularities, the universe will end in a singular state after a finite proper time and geometrical invariants of the…

General Relativity and Quantum Cosmology · Physics 2012-07-06 John D. Barrow , Antonio B. Batista , Giuseppe Dito , Julio C. Fabris , M. J. S. Houndjo

General relativity successfully describes space-times at scales that we can observe and probe today, but it cannot be complete as a consequence of singularity theorems. For a long time there have been indications that quantum gravity will…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald

Form factors constitute the key building block when organising the gravitational dynamics in terms of a curvature expansion. They generalise the concept of momentum-dependent couplings to curved spacetime. Moreover, they may capture…

High Energy Physics - Theory · Physics 2021-11-25 Benjamin Knorr , Chris Ripken , Frank Saueressig

A finite and unitary nonlocal formulation of quantum gravity is applied to the cosmological constant problem. The entire functions in momentum space at the graviton-standard model particle loop vertices generate an exponential suppression…

General Relativity and Quantum Cosmology · Physics 2016-02-08 J. W. Moffat

In classical general relativity, the generic approach to the initial singularity is very complicated as exemplified by the chaos of the Bianchi IX model which displays the generic local evolution close to a singularity. Quantum gravity…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Martin Bojowald , Ghanashyam Date

The occurrence of singularities where spacetime curvature becomes infinite and geodesic evolution breaks down are inevitable events in classical general relativity (GR) unless one chooses an exotic matter violating weak energy condition.…

General Relativity and Quantum Cosmology · Physics 2024-11-05 Bao-Fei Li , Parampreet Singh

Non-local gravity terms have a relevant role in determining the cosmological dynamics. Here we consider curvature- and torsion-based cosmological models where non-local terms can be ``scalarised'' and then reduced under the standard of…

General Relativity and Quantum Cosmology · Physics 2026-03-24 Salvatore Capozziello , Gaetano Lambiase , Giuseppe Meluccio

We propose a phenomenological approach to the cosmological constant problem based on generally covariant non-local and acausal modifications of four-dimensional gravity at enormous distances. The effective Newton constant becomes very small…

High Energy Physics - Theory · Physics 2007-05-23 Nima Arkani-Hamed , Savas Dimopoulos , Gia Dvali , Gregory Gabadadze

We show that the non-locality recently identified in quantum gravity using resummation techniques propagates to the matter sector of the theory. We describe these non-local effects using effective field theory techniques. We derive the…

High Energy Physics - Theory · Physics 2017-11-28 S. O. Alexeyev , X. Calmet , B. N. Latosh

Quantum cosmology implies corrections to the classical equations of motion which may lead to significant departures from the classical trajectory, especially at high curvature near the big-bang singularity. Corrections could in principle be…

General Relativity and Quantum Cosmology · Physics 2014-09-09 Martin Bojowald , David Simpson

In this paper, we investigate the consequences of maximal length as well as minimal momentum scales on nonlocal correlations shared by two parties of a bipartite quantum system. To this aim, we rely on a general phenomenological scheme…

Quantum Physics · Physics 2023-08-21 Pasquale Bosso , Fabrizio Illuminati , Luciano Petruzziello , Fabian Wagner

I argue that the linearity of quantum mechanics is an emergent feature at the Planck scale, along with the manifold structure of space-time. In this regime the usual causality violation objections to nonlinearity do not apply, and nonlinear…

Quantum Physics · Physics 2009-11-10 George Svetlichny

Loop quantum gravity introduces strong non-perturbative modifications to the dynamical equations in the semi-classical regime, which are responsible for various novel effects, including resolution of the classical singularity in a Friedman…

High Energy Physics - Theory · Physics 2007-05-23 Martin Bojowald , Roy Maartens , Parampreet Singh

Independent studies by different authors have proposed that classicality may be induced in quantum objects by cosmological constraints presented by an expanding universe of finite extent in space-time. Cosmological effects on a quantum…

General Physics · Physics 2010-11-25 C. L. Herzenberg

I introduce the spatial curvature effects inside the formalism of Relative Locality as a non-commutative structure of the momentum space in agreement with the very well known concepts of Quantum Groups. This gives a natural red-shift effect…

General Relativity and Quantum Cosmology · Physics 2013-11-19 Ivan Arraut

It is known that in loop quantum cosmology (LQC) the universe avoids the singularity by a bounce when the matter density approaches the critical density $\rho_c$ (the order of Planck density). After incorporating the inverse volume…

General Relativity and Quantum Cosmology · Physics 2011-03-14 Hua-Hui Xiong , Jian-Yang Zhu