MG14 - Talk detail |
|
Participant |
Moriconi, Riccardo | |||||||
|
Institution |
Dipartimento di Fisica, Universita di Napoli "Federico II" - INFN Sezione di Napoli - Via Cinthia - Napoli - Campania - Italy | |||||||
|
Session |
AT1 |
Accepted |
|
Order |
Time |
|||
|
Talk |
Oral abstract |
Title |
Chaos Removal in the R + qR2 gravity: the Mixmaster model | |||||
| Coauthors | ||||||||
|
Abstract |
We study the asymptotic dynamics of the Mixmaster Universe, near the cosmological singularity, considering f(R) gravity up to a quadratic corrections in the Ricci scalar R. The analysis is performed in the scalar-tensor framework and adopting Misner-Chitre-like variables to describe the Mixmaster Universe, whose dynamics resembles asymptotically a billiard-ball in a given domain of the half-Poincare space. The form of the potential well depends on the spatial curvature of the model and on the particular form of the self-interacting scalar field potential. We demonstrate that the potential walls determine an open domain in the con guration region, allowing the point-Universe to reach the absolute of the considered Lobachevsky space. In other words, we outline the existence of a stable fi nal Kasner regime in the Mixmaster evolution, implying the chaos removal near the cosmological singularity. |
|||||||
Pdf file |
||||||||
|
Session |
EU1 |
Accepted |
|
Order |
Time |
|||
|
Talk |
Oral abstract |
Title |
Semiclassical and quantum behavior of the Mixmaster model in the polymer approach | |||||
| Coauthors | ||||||||
|
Abstract |
We analyze the quantum dynamics of the Bianchi Type IX model, as described in the so-called polymer representation of quantum mechanics, to characterize the modi fications that a discrete nature in the anisotropy variables of the Universe induces on the morphology of the cosmological singularity. We fi rst perform a semiclassical analysis, to be regarded as the zeroth-order of a WKB (Wentzel-Kramers-Brillouin) approximation of the quantum dynamics, and demonstrate how the features of polymer quantum mechanics are able to remove the chaotic properties of the Bianchi IX dynamics. Then, we address the study of the full quantum dynamics of this model in the polymer representation and analyze the two cases, in which the Bianchi IX spatial curvature does not aff ect the wave-packet behavior, as well as the instance, for which it plays the role of an infi nite potential con fining the dynamics of the anisotropic variables. The main development of this analysis consists of investigating how, diff erently from the standard canonical quantum evolution, the high quantum number states associated to the anisotropies are not preserved arbitrarily close to the cosmological singularity. |
|||||||
Pdf file |
||||||||