Quintessential phenomena in higher-dimensional space-time

Abstract

Higher-dimensional cosmology provides a natural setting to treat, at a classical level, the cosmological effects of vacuum energy. Here we discuss two situations: in the first case we start with an ordinary matter field without any equation of state and end up with a generalized Chaplygin type of gas apparently as a consequence of extra dimensions. In the second case we introduce a priori a Chaplygin type of gas to study quintessential phenomena in higher-dimensional spacetime. The first case suffers from the disqualification that no dimensional reduction occurs, which is, however, rectified in the second case. Both models show the sought-after feature of occurrence of a flip in the expansion rate. It is observed that with the increase of dimensions the occurrence of a flip is delayed in both models, more in line with current observational requirements. Interestingly, we see that, depending on some initial conditions, our model admits QCDM, ΛCDM and also phantom-like evolution within a unified framework. Our solutions are general in nature in the sense that when the extra dimensions are switched off, the known 4D model is recovered. A correspondence to a recent work of Guo et al. on a quiessence-likemodel is also found.