Echoes of charged black-bounce spacetimes

TL;DR

This paper investigates scalar and electromagnetic field evolution in charged black-bounce spacetimes, revealing echo signals linked to spacetime properties and analyzing quasinormal modes across different parameter regimes.

Contribution

It provides new insights into the behavior of fields and signals in charged black-bounce spacetimes, including conditions for echoes and transitions to wormhole or regular black hole states.

Findings

Echo signals occur under specific charge and parameter conditions.

Transition from echoes to quasinormal ringdown when charge exceeds mass.

Charged black-bounce can be a regular black hole or a traversable wormhole depending on parameters.

Abstract

In present work, the evolution of scalar field and electromagnetic field under the background of the charged black-bounce spacetimes are investigated, and we obtain an obvious echoes signal which appropriately reports the properties of the charged black-bounce spacetimes and disclose the physical reasons behind such phenomena. Furthermore, by studying the quasinormal ringdown, we analyze the three states of the charged black-bounce spacetimes in detail, our results show that the echoes signal only appears when $(\rvert {Q}\rvert \le m)$ and $(\rvert {l}\rvert > m+ \sqrt{m ^{2}-Q^{2} })$ in this spacetime, while when the parameters demand $(\rvert {Q}\rvert>m)$, the echoes signal will be transformed into a quasinormal ringdown of the two-way traversable wormhole, and the charged black-bounce is a regular black hole with normal horizons by requiring $(\rvert {Q}\rvert \le m)$ and $(\rvert {l}\rvert < m- \sqrt{m ^{2}-Q^{2} })$.