Hyperbolically Symmetric Versions of Lemaitre-Tolman-Bondi Spacetimes

We study fluid distributions endowed with hyperbolical symmetry, which share many common features with Lemaitre-Tolman-Bondi (LTB) solutions (e.g. they are geodesic, shearing, non--conformally flat and the energy density is inhomogeneous). As such they may be considered as hyperbolically symmetric versions of LTB, with spherical symmetry replaced by hyperbolical symmetry. We start by considering pure dust models, and afterwards we extend our analysis to dissipative models with anisotropic pressure. In the former case the complexity factor is necessarily non-vanishing, whereas in the latter cases models with vanishing complexity factor are found. The remarkable fact is that all solutions satisfying the vanishing complexity condition are necessarily non-dissipative and satisfy the stiff equation of state.
Comment: 11 pages Latex. Published in Entropy (Special Issue:Complexity of self-gravitating systems). arXiv admin note: text overlap with arXiv:2109.07758