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L'emergenza dello spazio-tempo nella gravità quantistica e nella cosmologia quantistica
Philosophy Kitchen, 2019 Our best description of spacetime is provided by general relativity – yet, this theory is not thought to be fundamental. Instead, it is expected to be replaced by a theory of quantum gravity, which may not feature spacetime fundamentally.
Karen Crowther
doaj +1 more source
Switching Internal Times and a New Perspective on the `Wave Function of the Universe’
Universe, 2019 Despite its importance in general relativity, a quantum notion of general covariance has not yet been established in quantum gravity and cosmology, where, given the a priori absence of coordinates, it is necessary to replace classical frames with ...
Philipp A. Höhn
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A Brief Introduction to Loop Quantum Cosmology [PDF]
, 2009 In recent years, Loop Quantum Gravity has emerged as a solid candidate for a nonperturbative quantum theory of General Relativity. It is a background independent theory based on a description of the gravitational field in terms of holonomies and fluxes ...
Marugan, Guillermo A. Mena
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On the propagation across the big bounce in an open quantum FLRW cosmology. [PDF]
Eur Phys J C Part Fields, 2022 The propagation of a scalar field in an open FLRW bounce-type quantum spacetime is examined, which arises within the framework of the IKKT matrix theory.
Battista E, Steinacker HC.
europepmc +3 more sources
Does a Theory of Everything Exist?
Философия и космология, 2021 Since Einstein’s failure to define a Grand Unified Theory, physicists have pursued a comprehensive theory explaining nature, a Theory of Everything. But because General Relativity, Quantum Field Theory, and Cosmology have little in common, defining one ...
James R Johnson
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Einstein and Rastall theories of gravitation in comparison
European Physical Journal C: Particles and Fields, 2018 We profit by a recent paper of Visser claiming that Rastall gravity is equivalent to Einstein gravity to compare the two gravitational theories in a general way. Our conclusions are different from Visser’s ones.
F. Darabi +4 more
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$$f(\mathcal {G})$$ f(G) Noether cosmology
European Physical Journal C: Particles and Fields, 2020 We develop the n-dimensional cosmology for $$f(\mathcal {G})$$ f(G) gravity, where $$\mathcal {G}$$ G is the Gauss–Bonnet topological invariant. Specifically, by the so-called Noether Symmetry Approach, we select $$f(\mathcal {G})\simeq \mathcal {G}^k ...
Francesco Bajardi, Salvatore Capozziello
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Gen.Rel.Grav.40:1967-1980,2008, 2008 We have quantized a flat cosmological model in the context of the metric f(R) models, using the causal Bohmian quantum theory. The equations are solved and then we have obtained how the quantum corrections influence the classical equations.
arxiv +1 more source
Singularity: Raychaudhuri Equation once again [PDF]
, 2007 I first recount Raychaudhuri's deep involvement with the singularity problem in general relativity. I then argue that precisely the same situation has arisen today in loop quantum cosmology as obtained when Raychaudhuri discovered his celebrated equation.
A. A. Penzias +22 more
core +3 more sources