Inhomogeneous cosmological models such as the Stephani universes could, in principle, provide an explanation for the observed accelerated expansion of the Universe. It has, however, been argued recently that Stephani models cannot be consistent with observations unless its inhomogeneity parameter is sufficiently small, which renders the model ineffective in explaining the accelerated expansion without also including a cosmological constant. Working with a concrete, popular model of the Stephani cosmology, we expound upon this claim. In addition to observational constraints, we also study the entropic aspects of the Stephani model. We found that the situation is in fact similar to the LTB models, which despite satisfying the holographic principle, has difficulty satisfying all the constraints from observations.
Y. Ong, S. Hashemi, R. An, et. al.
Thu, 7 Dec 17