Spherically symmetric inhomogeneous model with Chaplygin gas

TL;DR

This paper models the universe's late-time acceleration using a spherically symmetric inhomogeneous spacetime with Chaplygin gas, revealing non-synchronous cosmic acceleration and potential bouncing behavior, extending previous homogeneous models.

Contribution

It introduces a new inhomogeneous cosmological model with Chaplygin gas that generalizes homogeneous solutions and explores inhomogeneity effects on cosmic acceleration and bouncing scenarios.

Findings

Universe exhibits late-time acceleration with inhomogeneity.

Deceleration parameter flip occurs non-synchronously across shells.

Model reduces to known homogeneous solutions when inhomogeneity is absent.

Abstract

We investigate the late time acceleration with a Chaplygin type of gas in spherically symmetric inhomogeneous model. At the early phase we get Einstien-deSitter type of solution generalised to inhomogeneous spacetime. But at late stage of the evolution our solutions admit the accelerating nature of the universe. For a large scale factor our model behaves like a ?CDM model. We calculate the deceleration parameter for this anisotropic model, which, unlike its homogeneous counterpart, shows that the flip is not syn- chronous occurring early at the outer shells. This is in line with other physical processes in any inhomogeneous models. Depending upon initial conditions our solution also gives bouncing universe. In the absence of inhomogeneity our solution reduces to wellknown solutions in homogeneous case. We have also calculated the effective deceleration parameter in terms of Hubble parameter. The whole situation is later discussed with the help of wellknown Raychaudhury equation and the results are compared with the previous case. This work is an extension of our recent communication where an attempt was made to see if the presence of extra dimensions and/or inhomogeneity can trigger an inflation in a matter dominated Lemaitre Tolman Bondi model.