Scalar-tensor black holes coupled to Born-Infeld nonlinear electrodynamics

Abstract

The non-existence of asymptotically flat, neutral black holes and asymptotically flat, charged black holes in the Maxwell electrodynamics, with non-trivial scalar field has been proved for a large class of scalar-tensor theories. The noscalar-hair theorems, however, do not apply in the case of non-linear electrodynamics. In the present work numerical solutions describing charged black holes coupled to Born-Infeld type non-linear electrodynamics in scalar-tensor theories of gravity with massless scalar field are found. The causal structure and properties of the solutions are studied, and a comparison between these solutions and the corresponding solutions in the General Relativity is made. The presence of the scalar field leads to a much more simple causal structure. The present class of black holes has a single, non-degenerate horizon, i.e., its causal structure resembles that of the Schwarzschild black hole.

Phases of 4d Scalar–tensor Black Holes Coupled to Born–infeld Nonlinear Electrodynamics

“…Hence, the electro-magnetic field acts as a source of the scalar field and allows the existence of asymptotically flat, hairy black holes. Such solutions have been found recently in different non-linear electrodynamics [1,2]. These solutions are hairy in a sense that the scalar field is not trivial.…”

“…In the present work we consider the same STT and find multiple-phase black-hole solutions numerically. Unlike the situation in [1,2], they are not determined in a unique way by the values of their magnetic charge and mass and the value of the scalar field at infinity. The phase diagram of the present solutions is reminiscent of the phase transition between caged black holes and black strings in higher dimensions [35,36].…”

“…Recent results show that when non-linear electrodynamics is considered the no-scalar-hair theorems in the scalar-tensor theories (STT) of gravity, which are valid for the cases of neutral black holes and charged black holes in the Maxwell electrodynamics, can be circumvented [1,2]. What is even more, in the present work, we find new non-unique, numerical solutions describing charged black holes coupled to non-linear electrodynamics in a special class of scalar-tensor theories.…”

Topological Born–Infeld-dilaton black holes

“…In the absence of dilaton field, exact solutions of Einstein-Born-Infeld theory with/without cosmological constant have been constructed in [26,27,28,29,30,31,32,33]. In the scalar-tensor theories of gravity, black hole solutions coupled to a Born-Infeld nonlinear electrodynamics have also been studied recently in [34].…”

Thermodynamical Properties of Topological Born–infeld-Dilaton Black Holes

“…In the absence of a dilaton field, exact solutions of Einstein-Born-Infeld theory with/without cosmological constant have been constructed by many authors [6,7,8,9,10,11,12,13]. In the scalar-tensor theories of gravity, black hole solutions coupled to a Born-Infeld nonlinear electrodynamics have been studied in [14]. The Born-Infeld action coupled to a dilaton field, appears in the low energy limit of open superstring theory [2].…”