Dynamic generation or removal of a scalar hair

TL;DR

This paper investigates the nonlinear dynamical processes of scalar hair generation and removal in black holes with scalar fields coupled to curvature invariants, using simulations of evolving gravitational systems.

Contribution

It provides the first detailed analysis of both scalarization and descalarization processes in dynamical black hole evolution with non-minimal scalar couplings.

Findings

Scalar hair can be dynamically generated or removed depending on initial conditions.

The evolution exhibits rich phase structures influenced by perturbation strength and parameters.

Both scalarization and descalarization processes are observed in simulations.

Abstract

We study dynamic processes through which the scalar hair of black holes is generated or detached in a theory with a scalar field non-minimally coupled to Gauss-Bonnet and Ricci scalar invariants. We concentrate on the nonlinear temporal evolution of a far-from-equilibrium gravitational system. In our simulations, we choose the initial spacetime to be either a bald Schwarzschild or a scalarized spherically symmetric black hole. Succeeding continuous accretion of the scalar field onto the original black hole, the final fate of the system displays intriguing features, which depend on the initial configurations, strengths of the perturbation, and specific metric parameters. In addition to the scalarization process through which the bald black hole addresses scalar hair, we observe the dynamical descalarization, which removes scalar hair from an original hairy hole after continuous scalar field accretion. We examine the temporal evolution of the scalar field, the metrics, and the Misner-Sharp mass of the spacetime and exhibit rich phase structures through nonlinear dynamical processes.