Results 61 to 70 of about 2,756,107 (244)

Cosmological perturbations in a class of fully covariant modified theories: application to models with the same background as standard LQC

European Physical Journal C: Particles and Fields, 2018
Bouncing cosmologies are obtained by adding to the Einstein–Hilbert action a term of the form $$\sqrt{-\,g}f(\chi )$$ -gf(χ) , with $$\chi $$ χ a scalar depending on the Hubble parameter only, not on its derivatives, and which is here shown to arise from
Jaume de Haro, Llibert Aresté Saló, Emilio Elizalde   +2 more
doaj   +1 more source

Two-photon amplitude interferometry for precision astrometry

The Open Journal of Astrophysics, 2022
Improved quantum sensing of photons from astronomical objects could provide high resolution observations in the optical benefiting numerous fields, including general relativity, dark matter studies, and cosmology.
Paul Stankus, Andrei Nomerotski, Anže Slosar, Stephen Vintskevich   +3 more
doaj   +1 more source

Non-commutative classical and quantum fractionary cosmology: anisotropic Bianchi type I case [PDF]

General Relativity and Gravitation
In this work, we will explore the effects of non-commutativity in fractional classical and quantum schemes using the anisotropicc Bianchi Type I cosmological model coupled to a scalar field in the K-essence formalism.
J. Socorro, J. J. Rosales, Leonel Toledo-Sesma   +2 more
semanticscholar   +1 more source

Reply to the comment on "Quantum priniple of relativity" [PDF]

, 2022
We refute criticisms by Del Santo and Horvat towards our paper "Quantum principle of relativity": most of their counterarguments can be dismissed, and the rest provides further evidence to our claims.
arxiv   +1 more source

The Einstein static universe in Loop Quantum Cosmology [PDF]

, 2007
Loop Quantum Cosmology strongly modifies the high-energy dynamics of Friedman-Robertson-Walker models and removes the big-bang singularity. We investigate how LQC corrections affect the stability properties of the Einstein static universe.
Arrowsmith C K, Ashtekar A, Ashtekar A, Barrow J D, Bojowald M, Eddington A S, Eddington A S, Ellis G F R, Ellis G F R, Gergely L A, Guth A H, Guth A H, Harrison E R, Kevin Vandersloot, Luca Parisi, Marco Bruni, Mukherjee S, Rebhan E, Rovelli C, Roy Maartens, Thiemann T   +20 more
core   +2 more sources

On Quantum Cosmology in Teleparallel Gravity [PDF]

Journal of Physics: Conf. Series 965 (2018) 012014, 2018
A quantum cosmology in teleparallel gravity is presented in this article. Teleparallel gravity is used to perform such an analysis once in General Relativity (GR) the concept of gravitational energy is misleading preventing the establishment of a concise quantum cosmology. The Wheeler-DeWitt like equation is obtained using the Weyl quantization and the
arxiv   +1 more source

Brane-world gravity [PDF]

, 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
core   +3 more sources

Quantum vacuum energy in general relativity [PDF]

, 2017
The paper deals with the scale discrepancy between the observed vacuum energy in cosmology and the theoretical quantum vacuum energy (cosmological constant problem).
C. Henke
semanticscholar   +1 more source

Classical and quantum cosmology of K-essentially modified $$R^2$$ and pure $$R^p$$ gravity [PDF]

General Relativity and Gravitation, 2018
We present a gravitational action with a modified higher order term of a combination of scalar curvature and Lagrangian density of a scalar field. This type of models has been considered first by Cruz-Dombriz et al.
N. Kan, Kiyoshi Shiraishi, Mai Yashiki
semanticscholar   +1 more source

Dynamics of the cosmological and Newton's constant [PDF]

, 2015
A modification of general relativity is presented in which Newton's constant and the cosmological constant become a conjugate pair of dynamical variables.
arxiv   +1 more source