Inhomogeneous and Radiating Composite Fluids.

Byron P Brassel,Sunil D Maharaj,Rituparno Goswami

doi:10.3390/e23111400

Abstract

We consider the energy conditions for a dissipative matter distribution. The conditions can be expressed as a system of equations for the matter variables. The energy conditions are then generalised for a composite matter distribution; a combination of viscous barotropic fluid, null dust and a null string fluid is also found in a spherically symmetric spacetime. This new system of equations comprises the energy conditions that are satisfied by a Type I fluid. The energy conditions for a Type II fluid are also presented, which are reducible to the Type I fluid only for a particular function. This treatment will assist in studying the complexity of composite relativistic fluids in particular self-gravitating systems.

Highlights

An interesting approach in the study of self-gravitating systems is the idea of complexity
A simple and physically quantifiable idea was recently investigated by [1]; it was proposed that relativistic fluids, with homogeneous energy density and isotropic pressure, are characterised with minimal complexity factors
Complexity is encoded in a structure scalar containing components from inhomogeneity, in the energy density, and local anisotropy arising from shear viscosity

Summary

Introduction

An interesting approach in the study of self-gravitating systems is the idea of complexity. A simple and physically quantifiable idea was recently investigated by [1]; it was proposed that relativistic fluids, with homogeneous energy density and isotropic pressure, are characterised with minimal complexity factors This approach is useful in the study of compact objects and radiating stars. Several studies have applied the ideas of Herrera [1] to general relativity [2,3,4,5,6,7,8,9,10,11], and modified gravity theories, especially Einstein–Gauss–Bonnet gravity [12] Another general concept that may be applied to self-gravitating fluids is energy conditions [13]. Our results may be helpful in analysing physical quantities associated with complexity in self-gravitating systems

Objectives

Discussion

Conclusion