A critical review of classical bouncing cosmologies
From MaRDI portal
Publication:2405354
DOI10.1016/J.PHYSREP.2014.12.004zbMATH Open1370.83107arXiv1406.2790OpenAlexW3103421916MaRDI QIDQ2405354
Author name not available (Why is that?)
Publication date: 25 September 2017
Published in: (Search for Journal in Brave)
Abstract: Given the proliferation of bouncing models in recent years, we gather and critically assess these proposals in a comprehensive review. The Planck data shows an unmistakably red, quasi scale-invariant, purely adiabatic primordial power spectrum and no primary non-Gaussianities. While these observations are consistent with inflationary predictions, bouncing cosmologies aspire to provide an alternative framework to explain them. Such models face many problems, both of the purely theoretical kind, such as the necessity of violating the NEC and instabilities, and at the cosmological application level, as exemplified by the possible presence of shear. We provide a pedagogical introduction to these problems and also assess the fitness of different proposals with respect to the data. For example, many models predict a slightly blue spectrum and must be fine-tuned to generate a red spectral index; as a side effect, large non-Gaussianities often result. We highlight several promising attempts to violate the NEC without introducing dangerous instabilities at the classical and/or quantum level. If primordial gravitational waves are observed, certain bouncing cosmologies, such as the cyclic scenario, are in trouble, while others remain valid. We conclude that, while most bouncing cosmologies are far from providing an alternative to the inflationary paradigm, a handful of interesting proposals have surfaced, which warrant further research. The constraints and lessons learned as laid out in this review might guide future research.
Full work available at URL: https://arxiv.org/abs/1406.2790
No records found.
No records found.
This page was built for publication: A critical review of classical bouncing cosmologies
Report a bug (only for logged in users!)Click here to report a bug for this page (MaRDI item Q2405354)
