Higher-dimensional black hole solutions with scalar hair and dilaton field and toroidal horizons and interior solution

Abstract

In this paper we investigate the black hole solutions with toroidal horizons in scalar hair/dilaton gravity. First, we obtain the field equations in n-dimensions, then we propose some different models(Ansatz) and find the exact solutions for these type of ansatzs. These solutions are not asymptotically (anti-)de Sitter or flat, except in one special case. We also show that the BTZ and BTZ-like
 solutions will emerge from some of these solutions as a special case. We also show that when the event horizon radius gets bigger and bigger, the temperature will be the same in various dimensions. The only difference is noticeable near the origin(this statement is clear in diagrams). For these solutions, we obtained a new version of the Smarr formula as well. Also, we show that the presence of the scalar field makes the black holes to be more stable near the origin except for the BTZ case. We can say in general that the presence of scalar field is an important factor in black hole’s stability investigations. In the critical behavior analysis we find that there is no evidence to show the existence of P-V criticality. We present here a class of interior solutions corresponding to the solution in scalar hair gravity exterior. The solution which is obtained in linear case is regular and well-behaved at the stellar interior.