Letter: Spherically Symmetric Metrics with Shear Controlling Expansion

Abstract

An isotropic spatially inhomogeneous spacetime with the stress tensor satisfying the limiting case of the strong energy condition [T₀₀ + 1/2)T] = 0 in the locally inertial coordinates where the observer's four-velocity is u ^a = δ₀ ^a satisfying the constraint u ^a u_a = −1 is studied. Special metrics with accelerating expansions of the inhomogeneous spacetime merely controlled by the shear are presented as an alternative model.