Results 21 to 30 of about 50,468 (222)
Exactly solvable quantum cosmologies from two killing field reductions of general relativity
Nuclear Physics B, 1989 Abstract An exact and, possibly, general solution to the quantum constraints is given for the sector of general relativity containing cosmological solutions with two space-like, commuting, Killing fields. The dynamics of these model space-times, which are known as Gowdy space-times, is formulated in terms of Ashtekar's new variables. The quantization
Viqar Husain, Lee Smolin
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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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Braneworlds and Quantum States of Relativistic Shells [PDF]
, 2007 We review some applications of relativistic shells that are relevant in the context of quantum gravity/quantum cosmology. Using a recently developed approach, the stationary states of this general relativistic system can be determined in the ...
Ansoldi, Stefano
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DeWitt boundary condition is consistent in Hořava-Lifshitz quantum gravity
Physics Letters B, 2022 In quantum cosmology the DeWitt boundary condition is a proposal to set the wave function of the universe to vanish at the classical big-bang singularity.
Hiroki Matsui +2 more
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, 2003 The observable universe could be a 1+3-surface (the "brane") embedded in a 1+3+d-dimensional spacetime (the "bulk"), with standard-model particles and fields trapped on the brane while gravity is free to access the bulk.
Maartens, Roy
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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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Minisuperspace Quantum Cosmology in Metric and Affine Theories of Gravity
Universe, 2022 Minisuperspace Quantum Cosmology is an approach by which it is possible to infer initial conditions for dynamical systems which can suitably represent observable and non-observable universes. Here we discuss theories of gravity which, from various points
Salvatore Capozziello, Francesco Bajardi
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Vanishing Cosmological Constant in Modified Gauss-Bonnet Gravity with Conformal Anomaly [PDF]
, 2006 We consider dark energy cosmology in a de Sitter universe filled with quantum conformal matter. Our model represents a Gauss-Bonnet model of gravity with contributions from quantum effects. To the General Relativity action an arbitrary function of the GB
Bergshoeff E. A. +18 more
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