Echoes from asymmetric wormholes and black bounce

The time evolutions of the field perturbations in certain asymmetric wormhole and black bounce backgrounds are investigated. It is found that the echo signals arise only in some wormhole cases. We examine the influences of these wormhole echoes by their mass and charge, as well as the asymmetry of spacetime. The results show that a massive wormhole with smaller charge is easier to observe echo signals. Particularly, the asymmetry of wormhole spacetime causes lower frequency echoes. Besides, analytical results show that the negative regions of effective potentials are enclosed by the black hole horizons for a class of symmetric black bounce metrics. This suggests the stability of these symmetric metrics.

Automated summary

This article investigates the time evolutions of the field perturbations in certain asymmetric wormhole and black bounce backgrounds. It is found that echo signals only arise in certain wormhole cases. The influences of these wormhole echoes are examined considering their mass, charge, and the asymmetry of spacetime. The results indicate that a massive wormhole with a smaller charge is easier to observe echo signals. Moreover, the asymmetry of wormhole spacetime leads to lower frequency echoes. Additionally, analytical results demonstrate that the negative regions of effective potentials are enclosed by the black hole horizons for a class of symmetric black bounce metrics, suggesting the stability of these symmetric metrics.