Dynamical spontaneous scalarization in Einstein-Maxwell-scalar models in anti-de Sitter spacetime

TL;DR

This paper investigates the dynamical process of spontaneous scalarization of charged black holes in anti-de Sitter spacetime within Einstein-Maxwell-scalar models, revealing how various parameters influence the instability and evolution endpoints.

Contribution

It provides a detailed analysis of the dynamical scalarization process, including effects of non-minimal couplings, charge, and cosmological constant, and identifies conditions leading to different end states.

Findings

Scalar field and black hole mass grow exponentially during instability.

Horizon area never decreases despite negative energy near the horizon.

Large cosmological constant can prevent scalarization.

Abstract

The phenomenon of spontaneous scalarization of charged black holes has attracted a lot of attention. In this work, we study the dynamical process of the spontaneous scalarization of charged black hole in asymptotically anti-de Sitter spacetimes in Einstein-Maxwell-scalar models. Including various non-minimal couplings between the scalar field and Maxwell field, we observe that an initial scalar-free configuration suffers tachyonic instability and both the scalar field and the black hole irreducible mass grow exponentially at early times and saturate exponentially at late times. For fractional couplings, we find that though there is negative energy distribution near the black hole horizon, the black hole horizon area never decreases. But when the parameters are large, the evolution endpoints of linearly unstable bald black holes will be spacetimes with naked singularity and the cosmic censorship is violated. The effects of the black hole charge, cosmological constant and coupling strength on the dynamical scalarization process are studied in detail. We find that large enough cosmological constant can prevent the spontaneous scalarization.