Trapping Horizons of the Evolving Charged Wormhole and Black Bounce

TL;DR

This paper presents dynamic solutions in Einstein-Maxwell-scalar theory describing evolving charged black holes, wormholes, and their transitions, emphasizing trapping horizons as key tools for tracking these processes.

Contribution

It introduces a unified framework using trapping horizons to analyze the evolution and transition of charged black holes and wormholes in EMS theory.

Findings

Degenerate marginal trapped surface triggers transitions.

Wormhole to black hole conversion involves horizon splitting.

Black bounce/wormhole transition involves horizon type change.

Abstract

We obtain one family of dynamic solutions in the Einstein-Maxwell-scalar(EMS) theory. Our solutions could describe the evolving charged black(white) hole or wormhole and its transition, including the case of black bounce/wormhole transition. We compare different wormhole throat definitions and suggest that the usage of trapping horizons is the most suitable choice for tracking the evolution of the dynamic black(white) hole and wormhole, and their conversion in a unified framework. Then we research several evolving processes in the appropriate parameters region, including the charge, the initial condition for the scalar hair, and parameters in our EMS Lagrangian. The results show that the appearance of a degenerate marginal trapped surface is the crucial event for the conversion or transition, particularly in these cases: i) when the evolving wormhole converts to a black hole, the surface emerges and splits into two trapping horizons; ii) if the metric would become a black hole but finally fails, two trapping horizons combine as the surface and then vanish; iii) if the black bounce/wormhole transition happens, one single trapping horizon changes its type.