Emergent universe scenario in the Einstein–Gauss–Bonnet gravity with dilaton

Abstract

We obtain cosmological solutions which admit emergent universe (EU) scenario in the framework of Einstein Gauss-Bonnet gravity coupled with a dilaton field in four dimensions. The coupling parameter of the Gauss-Bonnet terms and the dilaton in the theory are determined for obtaining an EU scenario. The corresponding dilaton potential which admits such scenario is determined. It is found that the GaussBonnet (GB) terms coupled with a dilaton field plays an important role in describing the dynamics of the evolution of the early as well as the late universe. We note an interesting case where the GB term dominates initially in the asymptotic past regime, subsequently it decreases and thereafter its contribution in determining the dynamics of the evolution dominates once again. We note that the Einsteins static universe solution permitted here is unstable which the asymptotic EU might follow. We also compare our EU model with supernova data. * bcpaul@iucaa.ernet.in †

Emergent universe by tunneling

“…Another possibility for the Emergent Universe scenario is to consider models in which the scale factor asymptotically tends to a constant in the past [14,15,[25][26][27][28][29][30].…”

History of cosmic evolution with modified Gauss–Bonnet-dilatonic coupled term

“…it admits black-hole solutions [47][48][49][50][51] and gives rise to cosmic inflation at the early epoch [52]. Late-time accelerated expansion of the universe is particularly a very special feature of such an action [52][53][54][55][56][57]. Moreover, important issues like late-time dominance of dark energy after a scaling matter era, thus alleviating the coincidence problem crossing the phantom divide line, and compatibility with the observed spectrum of cosmic background radiation have also been addressed recently [58][59][60][61].…”

Observational constraints on EoS parameters of emergent universe

“…EU scenario has been explored with quintom matter [16] and further investigated the realization of the scenario with a non-conventional fermion field to obtain a scale invariant perturbation [17]. It has been shown that the EU scenario can be implemented successfully in the framework of general relativity [13] in addition to Gauss-Bonnet gravity [18]. The modified Gauss-Bonnet gravity as gravitational alternative for dark energy is however considered by Nojiri and Oddintsov [19].…”