The space-time structure of an untouchable naked singularity in superstrings theory

TL;DR

This paper explores the causal and topological structure of an exact Einstein-Maxwell-Dilaton solution, demonstrating how a ring singularity can be cloaked by a wormhole throat, supporting the Wormhole Cosmic Censorship conjecture within superstring theory.

Contribution

It introduces a detailed analysis of a five-parameter solution showing a naked singularity cloaked by a wormhole throat, extending the Cosmic Censorship conjecture to superstring-inspired spacetimes.

Findings

The ring singularity is cloaked by the wormhole throat, satisfying the Wormhole Cosmic Censorship.

The topology of the wormhole throat connects two regions instantaneously, with the singularity topologically identified.

The domain of outer communication includes a chronology-violating region supporting closed timelike curves.

Abstract

According to the Cosmic Censorship Conjecture, naked singularities are believed to be forbidden in nature and must remain hidden by an event horizon. In this work, we present the causal structure of an exact solution to the Einstein-Maxwell-Dilaton equations with five parameters: mass, angular momentum, electric and magnetic charges, and a scale, satisfying constraint equations. For one of the constraints, the solution represents a wormhole (WH), and for the other, a black hole (BH), both with an untouchable ring singularity causally disconnected from the rest of the universe. After topologically defining the concept of Wormhole Cosmic Censorship (WCC), we analyze its metric functions in Papapetrou coordinates to verify metric analyticity in spacetime, construct the Carter-Penrose diagram, and use Boyer-Linquist coordinates to visualize the cladding of the ring singularity by the throat. We conclude that the ring singularity in this WH is clad by the throat, similarly to how the event horizon clads the ring singularity in the Kerr-Newman black hole, thus satisfying the WCC Conjecture. In this work, we show that the topology of the WH throat is such that the two sides of the throat are separated by the singularity but topologically identified, resulting in an instantaneous connection between these two regions. These results are applicable to various theories, including Kaluza-Klein and superstring theory. We provide a rigorous proof that, in the black hole case, the domain of outer communication includes a chronology-violating region and thus supports the existence of closed timelike curves outside the event horizon.