We obtain cosmological four-dimensional solutions of the low-energy effective string theory by reducing a five-dimensional black hole, and black hole–de Sitter solution of the Einstein gravity down to four dimensions. The appearance of a cosmological constant in the five dimensional Einstein–Hilbert action produces a special dilaton potential in the four-dimensional effective string action. Cos...

We review some of the most striking properties of the phase diagrams of higher dimensional black holes in pure gravity. We focus on static black hole solutions with KaluzaKlein asymptotics and stationary black hole solutions in flat Minkowski space. Both cases exhibit a rich pattern of interconnected phases and merger points with topology changing transitions. In the first case, the phase diagr...

In the framework of gravothermal evolution an ideal monatomic fluid, I examine dynamical instability fluid sphere in ($N$+1) dimensions by exploiting Chandrasekhar's criterion to each quasistatic equilibrium along sequence evolution. Once is triggered, it would probably collapse into a black hole if no other interaction halts process. From this viewpoint, privilege (3+1)-dimensional spacetime m...