Wormholes without exotic matter: quasinormal modes, echoes and shadows

An analytical solution representing traversable asymptotically flat and symmetric wormholes was obtained without adding exotic matter in two different theories independently: in the Einstein-Maxwell-Dirac theory and in the second Randall-Sundrum brane-world model. Further, a smooth normalizable asymmetric wormhole solution has been recently obtained numerically in the Einstein-Maxwell-Dirac theory. Using the time-domain integration method we study quasinormal ringing of all these wormholes with emphasis to the regime of mimicking the near extremal Reissner-Nordstrom black holes, which is characterised by echoes. In addition, we calculate radius of shadows cast by these wormholes.

Automated summary

Analytical solutions for traversable asymptotically flat and symmetric wormholes have been obtained independently in two different theories, without the need for exotic matter. Additionally, a numerically obtained smooth normalizable asymmetric wormhole solution has been achieved in one of the theories. The study focuses on the quasinormal ringing of these wormholes, particularly in mimicking near extremal Reissner-Nordstrom black holes, and calculates the radius of shadows cast by the wormholes.