How to obtain a class of emergent universes with a general form of dissipation?

Abstract

In this paper, we have assumed a flat Friedmann-Lemaitré-Robertson-Walker universe endowed with a general form of dissipation. The source of dissipation is considered to be a bulk viscous pressure $\Pi$ which leads to an adiabatic creation of particles induced by the gravitational field. Further, the cosmic substratum is assumed to satisfy the equation of state $p=(\gamma -1)\rho$ and $\Pi$ is considered to be proportional to $H^{2k+1}$, where $H$ is the Hubble parameter and $k$ is the index of dissipation. This choice of dissipation is consistent with the pioneering works by Barrow and Clifton. Finally, by assuming an exponential form for $H$ given by $H=e^{m(t-t_0)}$, where $m$ is a positive real parameter and which bears all the signatures of an emergent universe, we have been able to establish that the sufficiency of the inequality $\gamma k\le 0$ can produce a class of emergent universes. However, this condition is by no means necessary for the existence of an emergent universe.

The author has withdrawn this submission due to errors identified in the manuscript. The issues will be corrected, and a revised version may be submitted at a later date