Unbraiding the bounce: superluminality around the corner

0502241 - FZÚ 2019 RIV GB eng J - Journal Article
Dobre, D.A. - Frolov, A.V. - Ghersi, J.T.G. - Ramazanov, Sabir - Vikman, Alexander
Unbraiding the bounce: superluminality around the corner.
Journal of Cosmology and Astroparticle Physics. Roč. 2018, č. 3 (2018), s. 1-20, č. článku 020. ISSN 1475-7516. E-ISSN 1475-7516
R&D Projects: GA MŠMT EF15_003/0000437
Grant - others:OP VVV - CoGraDS(XE) CZ.02.1.01/0.0/0.0/15_003/0000437
Institutional support: RVO:68378271
Keywords : alternatives to inflation * initial conditions and eternal universe * physics of the early universe * cosmic singularity
OECD category: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)
Impact factor: 5.524, year: 2018

We study a particular realization of the cosmological bounce scenario proposed recently by Ijjas and Steinhardt in [1]. First, we find that their bouncing solution starts from a divergent sound speed and ends with its vanishing. Thus, the solution connects two strongly coupled configurations. These pathologies are separated from the bouncing regime by only a few Planck times. We then reveal the exact structure of the Lagrangian, which reproduces this bouncing solution. This reconstruction allowed us to consider other cosmological solutions of the theory and analyze the phase space. In particular, we find other bouncing solutions and solutions with superluminal sound speed. These stable superluminal states can be continuously transformed into the solution constructed by Ijjas and Steinhardt. We discuss the consequences of this feature for a possible UV-completion.
Permanent Link: http://hdl.handle.net/11104/0294186