Naked Singularity and Thunderbolt

TL;DR

This paper investigates quantum effects near naked singularities by analyzing a scalar field in a simplified spacetime, revealing a thunderbolt phenomenon that could restore the spacetime's global hyperbolicity.

Contribution

It demonstrates the emergence of a thunderbolt along the Cauchy horizon due to boundary condition changes, suggesting a quantum mechanism for horizon destruction.

Findings

Thunderbolt appears along the Cauchy horizon.

Quantum effects may restore global hyperbolicity.

Results may apply to string-brane interactions.

Abstract

We consider quantum theoretical effects of the sudden change of the boundary conditions which mimics the occurrence of naked singularities. For a simple demonstration, we study a massless scalar field in $(1 + 1)$-dimensional Minkowski spacetime with finite spatial interval. We calculate the vacuum expectation value of the energy-momentum tensor and explicitly show that singular wave or {\em thunderbolt} appears along the Cauchy horizon. The thunderbolt possibly destroys the Cauchy horizon if its backreaction on the geometry is taken into account, leading to quantum restoration of the global hyperbolicity. The result of the present work may also apply to the situation that a closed string freely oscillating is traveling to a brane and changes itself to an open string pinned-down by the ends satisfying the Dirichlet boundary conditions on the brane.