Singularities in Cosmology

Topological Singularities in Cosmology

Inaccessible Singularities in Toral Cosmology

The familiar Bang/Crunch singularities of classical cosmology have recently been augmented by new varieties: rips, sudden singularities, and so on. These tend to be associated with final states. Here we consider an alternative possibility for the initial state: a singularity which has the novel property of being inaccessible to physically well-defined probes. These singularities arise naturally...

Towards quantum cosmology without singularities.

In this paper we investigate the vanishing of cosmological singularities by quantization. Starting from a 5d Kaluza{Klein approach we quantize, as a rst step, the non{spherical metric part and the dilaton eld. These elds which are classically singular become smooth after quantization. In addition, we argue that the incorporation of non perturbative quantum corrections form a dilaton potential. ...

Singularities in Inflationary Cosmology: A Review

We review here some recent results that show that inflationary cosmological models must contain initial singularities. We also present a new singularity theorem. The question of the initial singularity re-emerges in inflationary cosmology because inflation is known to be generically futureeternal. It is natural to ask, therefore, if inflationary models can be continued into the infinite past in...

Singularities in a scalar field quantum cosmology.

The quantum theory of a spatially at Friedmann-Robertson-Walker universe with a massless scalar eld as source is further investigated. The classical model is singular, and in the framework of a genuine canonical quantization (Arnowitt-Deser-Misner formalism) a discussion is made of the cosmic evolution, particularly of the quantum gravitational collapse problem. It is shown that in a matter-tim...