Emergent universe supported by chiral cosmological fields in 5D Einstein-Gauss-Bonnet gravity

We propose application of the chiral cosmological model (CCM) for the Einstein-Gauss-Bonnet (EGB) 5D theory of gravitation with the aim of finding new models of the Emergent Universe (EmU) scenario. We analyze an EmU supported by two chiral cosmological fields for a spatially flat universe, and with three chiral fields when investigating open and closed universes. To prove the validity of the spatially flat EmU scenario, we fix the scale factor and find an exact solution by decomposing the 5D EGB equations and solving the chiral field dynamics equation. The EGB equations are decomposed in such a way that the first chiral field is responsible for the Einstein part of the model while the second field, together with kinetic interaction term, is connected with the Gauss-Bonnet part of the theory. We proved that both fields are phantom in this decomposition and that the model has a solution if the kinetic interaction factor between the fields is constant. The solution is presented in terms of cosmic time. In the case of open and closed universes, we introduce the third chiral field (a canonical one for a closed universe and a phantom one for an open universe) which is responsible for the EGB and curvature parts. The solution of the third field equation is obtained in quadratures. Thus we have prove that the CCM is able to support the EmU scenario in 5D EGB gravity for spatially flat, open and closed universes.