[Tester la cosmologie quantique à boucles]
La cosmologie quantique à boucles prédit que les effets de la gravitation quantique résolvent la singularité du big-bang et la remplacent par un rebond cosmique. De plus, la cosmologie quantique à boucles peut aussi modifier la forme des perturbations cosmologiques primordiales, par exemple en réduisant l'énergie aux grandes échelles dans les modèles inflationnaires ou en diminuant le rapport tenseur/scalaire dans le scénario du matter bounce ; ces deux effets constituent des tests observationnels potentiels pour la cosmologie quantique à boucles. Dans cet article, je passe en revue ces prédictions, ainsi que d'autres, et aussi discute brièvement trois problèmes ouverts de la cosmologie quantique à boucles : sa relation avec la gravitation quantique à boucles, le problème trans-planckien et une possible transition d'un espace-temps lorentzien à un espace–temps euclidien autour du point de rebond.
Loop quantum cosmology predicts that quantum gravity effects resolve the big-bang singularity and replace it by a cosmic bounce. Furthermore, loop quantum cosmology can also modify the form of primordial cosmological perturbations, for example by reducing power at large scales in inflationary models or by suppressing the tensor-to-scalar ratio in the matter bounce scenario; these two effects are potential observational tests for loop quantum cosmology. In this article, I review these predictions and others, and also briefly discuss three open problems in loop quantum cosmology: its relation to loop quantum gravity, the trans-Planckian problem, and a possible transition from a Lorentzian to a Euclidean space–time around the bounce point.
Mot clés : Gravité quantique à boucles, Cosmologie quantique à boucles, Tests observationnels
@article{CRPHYS_2017__18_3-4_207_0,
author = {Edward Wilson-Ewing},
title = {Testing loop quantum cosmology},
journal = {Comptes Rendus. Physique},
pages = {207--225},
publisher = {Elsevier},
volume = {18},
number = {3-4},
year = {2017},
doi = {10.1016/j.crhy.2017.02.004},
language = {en},
}
Edward Wilson-Ewing. Testing loop quantum cosmology. Comptes Rendus. Physique, Volume 18 (2017) no. 3-4, pp. 207-225. doi : 10.1016/j.crhy.2017.02.004. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2017.02.004/
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Commentaires - Politique
Testing different approaches to quantum gravity with cosmology: An overview
Aurélien Barrau
C. R. Phys (2017)