https://doi.org/10.1140/epjp/s13360-023-04541-w
Regular Article
Non-singular flat universes in braneworld and loop quantum cosmology
1
Department of Physics, Aliah University, 700160, Kolkata, West Bengal, India
2
Department of Physics, University of North Bengal, 734 013, Siliguri, West Bengal, India
3
Department of Physics, Government College of Engineering and Ceramic Technology, 700 010, Kolkata, West Bengal, India
4
Department of Basic Sciences, Atria University, 560024, Bengaluru, Karnataka, India
Received:
10
September
2023
Accepted:
30
September
2023
Published online:
19
October
2023
In this paper we consider an exotic matter source with nonlinear Equation of state and a minimally coupled scalar field with two different potentials that produce a closed inflationary emergent universe in the relativistic context. We study all these three cases both in the context of Randall–Sundrum braneworld and effective Loop quantum cosmology (LQC) for vanishing spatial curvature that is observationally favored and in the absence of any effective cosmological constant term. We solve the modified Friedmann equations in each case to obtain the time evolution of the scale factor and use it to check whether the initial singularity can be averted. In almost all the cases we find the initial singularity is absent. We study the nature of the slow-roll inflation in the cases where we obtain inflationary emergent universes. The inflationary scenario is found to be improved than in a standard relativistic context and we compare the improved scenario for both the braneworld and LQC models. Interestingly, we also obtain bouncing and cyclic universes from our analysis in some cases. The initial singularity can be averted with the matter EoS or scalar field potential respecting the Null Energy condition, taking into account effective high energy (curvature) corrections with or without extra dimensions. The UV corrected scenario allows a spatially flat universe to behave effectively like a closed one and the initial singularity can be avoided by suitable bounce or emergence mechanisms as obtained.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
