Related papers: Spin-induced black hole spontaneous scalarization
Originally regarded as forbidden, black hole ``hair'' are fields associated with a stationary black hole apart from the gravitational and electromagnetic ones. Several stable stationary black hole solutions with gauge or Skyrme field hair…
As it became well known in the past years, Einstein-scalar-Gauss-Bonnet (EsGB) theories evade no-hair theorems and allow for scalarized compact objects including black holes (BH). The coupling function that defines the theory is the main…
Black hole spontaneous scalarization has been attracting more and more attention as it circumvents the well-known no-hair theorems. In this work, we study the scalarization in Einstein-scalar-Gauss-Bonnet theory with a probe scalar field in…
Black holes have a unique sensitivity to the presence of ultralight matter fields or modifications of the underlying theory of gravity. In the present paper we combine both features by studying an ultralight, dynamical scalar field that is…
No-hair theorems for scalar-tensor theories imply that the trivial scalar field configuration is the unique configuration around stationary black hole spacetimes. The most basic assumption in these theorems is that a constant scalar…
We study the spontaneous scalarization of Bardeen black holes, whose tachyonic instability triggers the formation of scalarized charged black holes (SCBHs). In this case, we find infinite ($n=0,1,2,\cdots$) branches of SCBHs with magnetic…
In the present paper we study the scalar sector of the quasinormal modes of charged general relativistic, static and spherically symmetric black holes coupled to nonlinear electrodynamics and embedded in a class of scalar-tensor theories.…
It is well-known that parity symmetry is broken in the weak interaction but conserved for Einstein's general relativity and Maxwell's electromagnetic theory. Nevertheless, parity symmetry could also be violated in the…
We study the consistency of Scalar Gauss-Bonnet Gravity, a generalization of General Relativity where black holes can develop non-trivial hair by the action of a coupling $F(\Phi){\cal G}$ between a function of a scalar field and the…
We explore purely metric theories of gravity with second-order equations of motion and a single additional, purely gravitational, propagating, scalar degree of freedom. We identify a subclass of these theories in which this scalar causes a…
We develop the effective theory for perturbations around black holes with scalar hair, in two directions. First, we show that the scalar-Gauss--Bonnet theory, often used as an example exhibiting scalar black hole hair, can be deformed by…
We present explicit black holes endowed with primary scalar hair within the shift-symmetric subclass of Beyond Horndeski theories. These solutions depend, in addition to the conventional mass parameter, on a second free parameter encoding…
Based on the hyperboloidal framework, we research the dynamical process of charged de Sitter black holes scattered by a charged scalar field. From the linear perturbation analysis, with the coupling strength within a critical interval, the…
We establish a no inner-horizon theorem for black holes with charged scalar hairs. Considering a general gravitational theory with a charged scalar field, we prove that there exists no inner Cauchy horizon for both spherical and planar…
In $U(1)$ gauge-invariant scalar-vector-tensor theories with second-order equations of motion, we study the properties of black holes (BH) on a static and spherically symmetric background. In shift-symmetric theories invariant under the…
We consider the quasinormal modes, quasibound states and superradiant instability of a rotating hairy black hole, which possesses a Horndeski hair as deviation from Kerr black hole, under the perturbation of massive scalar field. With the…
Scalar fields coupled to three-dimensional gravity are considered. We uncover a scaling symmetry present in the black hole reduced action, and use it to prove a Smarr formula valid for any potential. We also prove that non-rotating hairy…
The Einstein-Gauss-Bonnet gravity in five dimensions is extended by scalar fields and the corresponding equations are reduced to a system of non-linear differential equations. A large family of regular solutions of these equations is shown…
In a subclass of scalar-tensor theories, it has been shown that standard general relativity solutions of neutron stars and black holes with trivial scalar field profiles are unstable. Such an instability leads to solutions which are…
We propose a new model of black hole spontaneous scalarization that combines a scalar--Gauss--Bonnet interaction with a non--minimal coupling to a U(1) gauge field (a dark photon or an electromagnetic field). This construction generalizes…