Violation of cosmic censorship in Einstein-Maxwell-Scalar models with fractional coupling

TL;DR

This paper investigates how fractional coupling in Einstein-Maxwell-Scalar models can lead to violations of the weak cosmic censorship conjecture, showing potential formation of naked singularities through numerical simulations.

Contribution

It demonstrates that fractional coupling can cause negative energy densities and curvature growth, challenging the robustness of cosmic censorship in these models.

Findings

Scalarized black holes develop negative energy density near the horizon.

Strong fractional coupling induces rapid curvature growth and geometric degeneration.

Simulations suggest possible formation of naked singularities.

Abstract

The weak cosmic censorship conjecture plays a foundational role in classical gravity by asserting that spacetime singularities are generically hidden behind event horizons. In this work, we explore its robustness in the Einstein-Maxwell-Scalar theory with fractional coupling by studying both static black hole solutions and their fully nonlinear dynamical evolution. We identify a class of scalarized black holes that develop negative energy density near the event horizon, indicating violations of the classical energy conditions. Numerical evolutions of perturbed configurations reveal that sufficiently strong fractional coupling drives rapid curvature growth and geometric degeneration in the near-horizon region, accompanied by persistent negative energy density. While the simulations do not resolve the ultimate end state, the observed dynamics consistently point toward a weakening of the horizon-supporting structure and are suggestive of incipient naked singularity formation. These results uncover a classical mechanism through which fractional coupling can challenge the validity of the weak cosmic censorship conjecture in asymptotically flat spacetimes.