Results 21 to 30 of about 20,416 (75)

Quantum cosmology of the Big Rip: Within GR and in a modified theory of gravity

, 2017
Quantum gravity is the theory that is expected to successfully describe systems that are under strong gravitational effects while at the same time being of an extreme quantum nature.
M. Bouhmadi-López, Imanol Albarran, Che-Yu Chen   +2 more
semanticscholar   +1 more source

Measure problem in slow roll inflation and loop quantum cosmology [PDF]

, 2010
We consider the measure problem in standard slow-roll inflationary models from the perspective of loop quantum cosmology (LQC). Following recent results by Ashtekar and Sloan, we study the probability of having enough e-foldings and focus on its ...
Alejandro Corichi, A. Karami
semanticscholar   +1 more source

Simple quantum cosmology: Vacuum energy and initial state

, 2005
A static non-singular 10-dimensional closed Friedmann universe of Planck size, filled with a perfect fluid with an equation of state with w = -2/3, can arise spontaneously by a quantum fluctuation from nothing in 11-dimensional spacetime.
D. Spergel, D. Youm, E. Elbaz, M. Novello, M. Tegmark, S. Alexander, S. Eidelman, T. R. Mongan, T.R. Mongan   +8 more
core   +2 more sources

The Semiclassical Limit of Loop Quantum Cosmology [PDF]

, 2001
The continuum and semiclassical limits of isotropic, spatially flat loop quantum cosmology are discussed, with an emphasis on the role played by the Barbero-Immirzi parameter \gamma in controlling space-time discreteness.
Ashtekar A, Ashtekar A, Ashtekar A, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bombelli L, Bombelli L, Corichi A, Karasev M V, Martin Bojowald, Rovelli C, Sahlmann H, Thiemann T, Thiemann T, Varadarajan M   +20 more
core   +3 more sources

Can chaos be observed in quantum gravity?

, 2017
Full general relativity is almost certainly 'chaotic'. We argue that this entails a notion of nonintegrability: a generic general relativistic model, at least when coupled to cosmologically interesting matter, likely possesses neither differentiable ...
Dittrich, Bianca, Hoehn, Philipp A., Koslowski, Tim A., Nelson, Mike I.   +3 more
core   +1 more source

Loop Quantum Cosmology: Recent Progress

, 2004
Aspects of the full theory of loop quantum gravity can be studied in a simpler context by reducing to symmetric models like cosmological ones. This leads to several applications where loop effects play a significant role when one is sensitive to the ...
A Ashtekar, A Ashtekar, A Ashtekar, A Ashtekar, A Ashtekar, A Ashtekar, A Okolow, C Rovelli, C Rovelli, C Rovelli, C Rovelli, G M Hossain, G W Gibbons, J F Barbero, J Z Simon, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, M Bojowald, Martin Bojowald, P Singh, T Thiemann, T Thiemann, V A Belinskii, V Husain   +35 more
core   +1 more source

Quantum Effects on Cosmic Scales as an Alternative to Dark Matter and Dark Energy [PDF]

Universe
The spin-torsion theory is a gauge theory approach to gravity that expands upon Einstein’s general relativity (GR) by incorporating the spin of microparticles. In this study, we further develop the spin-torsion theory to examine spherically symmetric and
Daxiu Chen, Lin Wang
semanticscholar   +1 more source

A no-singularity scenario in loop quantum gravity

, 2012
Canonical methods allow the derivation of effective gravitational actions from the behavior of space-time deformations reflecting general covariance.
Ashtekar A, Ashtekar A, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Bojowald M, Cailleteau T Mielczarek J Barrau A Grain J, Date G, George M Paily, Henderson A Laddha A Tomlin C, Kreienbuehl A, Martin Bojowald, Perez A, Rendall A D, Reyes J D, Rovelli C, Rovelli C, Thiemann T, Thiemann T   +23 more
core   +1 more source

Loop Quantum Gravity: Four Recent Advances and a Dozen Frequently Asked Questions

, 2007
As per organizers' request, my talk at the 11th Marcel Grossmann Conference consisted of two parts. In the first, I illustrated recent advances in loop quantum gravity through examples.
Ashtekar, Abhay
core   +1 more source

Loop quantum gravity corrections to gravitational wave dispersion [PDF]

, 1997
Cosmological tensor perturbations equations are derived for Hamiltonian cosmology based on Ashtekar's formulation of general relativity, including typical quantum gravity effects in the Hamiltonian constraint as they are expected from loop quantum ...
Bojowald, Martin, Hossain, Golam Mortuza
core   +3 more sources