Cylindrically Symmetric Inhomogeneous Universes with a Cloud of Strings

Abstract

Cylindrically symmetric inhomogeneous string cosmological models are investigated in presence of string fluid as a source of matter. To get the three types of exact solutions of Einstein's field equations we assume A = f (x)k(t), B = g(x) (t) and C = h(x) (t). Some physical and geometric aspects of the models are discussed.

Does a cloud of strings affect shear viscosity bound?

“…It means the stronger the coupling, the weaker the shear viscosity per entropy density [19]. In this paper we consider massive gravity with a cloud of strings [20,21,22,23,24,25,26,27,28,29,30] and introduce the black brane solution. This model can be considered as a generalization of the Einstein-Hilbert model for studying the unknown part of the universe, dark matter and dark energy.…”

Critical Parameters for Big-Bang Thermal Explosion

“…Meanwhile our results imply that the small wavy roughness along boundaries of the annuli may delay a possible Big-Bang explosion and shift the critical (hot-spot) location. We will investigate other interesting issues [23,24] in the near future. Very high temperature (dimensionless) profiles for s = 0.6 after fine tuning of δ and μ. μ is related to the thermal absorptivity.…”

Cloud of strings in ${{f}}({{R}})$ gravity

“…This behavior implies that such an object should give rise to astrophysical and cosmological implications. Since then, several papers have been devoted to the study of string clouds in the General Relativity context [5][6][7][8][9] and for alternative theories of gravity [10][11][12][13][14][15].…”