Spontaneous scalarisation of charged black holes: coupling dependence and dynamical features
read the original abstract
Spontaneous scalarisation of electrically charged, asymptotically flat Reissner-Nordstr\"om black holes (BHs) has been recently demonstrated to occur in Einstein-Maxwell-Scalar (EMS) models. EMS BH scalarisation presents a technical simplification over the BH scalarisation that has been conjectured to occur in extended Scalar-Tensor Gauss-Bonnet (eSTGB) models. It is then natural to ask: 1) how universal are the conclusions extracted from the EMS model? And 2) how much do these conclusions depend on the choice of the non-minimal coupling function? Here we perform a comparative analysis of different forms for the coupling function including: exponential, hyperbolic, power-law and a rational function (fraction) couplings. In all of them we obtain and study the domain of existence of fundamental, spherically symmetric, scalarised BHs and compute, in particular, their entropy. The latter shows that scalarised EMS BHs are always entropically preferred over the RN BHs with the same total charge to mass ratio $q$. This contrasts with the case of eSTGB, where for the same power-law coupling the spherical, fundamental scalarised BHs are not entropically preferred over Schwarzschild. Also, while the scalarised solutions in the EMS model for the exponential, hyperbolic and power-law coupling are very similar, the rational function coupling leads to a transition in the domain of existence. Furthermore, fully non-linear dynamical evolutions of unstable RN BHs with different values of $q$ are presented. These show: 1) for sufficiently small $q$, scalarised solutions with (approximately) the same $q$ form dynamically; 2) for large $q$, spontaneous scalarisation visibly decreases $q$; thus evolutions are non-conservative; 3) despite the existence of non-spherical, static scalarised solutions, the evolution of unstable RN BHs under non-spherical perturbations leads to a spherical scalarised BH.
This paper has not been read by Pith yet.
Forward citations
Cited by 7 Pith papers
-
Binary Black Hole Coalescence and the Dynamics of Scalar Hair in Einstein-Maxwell-Scalar Theory
Numerical simulations of binary black hole coalescence in EMS theory show dynamic triggering of scalar hair depending on coupling strength and remnant charge.
-
Inspiral gravitational waveforms from charged compact binaries with scalar hair
In Einstein-scalar-Maxwell theories, charged compact binaries produce gravitational waveforms containing a leading -1 post-Newtonian dipole correction controlled by one deviation parameter b.
-
Spin-Induced Nonlinear Scalarization of Kerr Black Holes in Einstein-scalar-Gauss-Bonnet Gravity
Kerr black holes in an EsGB model without linear instability undergo nonlinear scalarization above spin 0.5, existing in a finite low-mass high-spin wedge rather than a narrow band.
-
Spin-charge induced scalarization of Kerr-Newman black holes in the Einstein-Maxwell-scalar theory with scalar potential
Kerr-Newman black holes in EMS theory with scalar potential scalarize for spins below a threshold set by charge, scalar mass, and coupling strength.
-
Critical phenomenon inside asymptotically flat black holes with spontaneous scalarization
Scalarized black holes in EMS theory lack smooth Cauchy horizons and form Kasner singularities, with a scaling relation between Kasner parameter and charge-to-mass ratio near criticality.
-
Scalarizations of magnetized Reissner-Nordstr\"om black holes induced by parity-violating and parity-preserving interactions
Magnetic fields lower the scalarization threshold for electromagnetic and gravitational Chern-Simons couplings but produce opposite trends on the two Gauss-Bonnet branches, with nonlinear terms converting exponential ...
-
Existence of nonlinearly scalarized black holes in Einstein-scalar-Gauss-Bonnet theory with polynomial couplings
Nonlinearly scalarized black holes exist in EsGB theory for couplings ζ(φ)=αφ⁴−βφ⁸ and ζ(φ)=αφ⁴−βφ⁶ (but not pure quartic), with instability thresholds for Gaussian pulses and universal probe-limit branches that depen...
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.