Scalar scattering by black holes and wormholes

TL;DR

This paper investigates how scalar waves scatter off black holes and wormholes, comparing numerical results with classical approximations, and finds distinctive scattering signatures for wormholes at certain frequencies.

Contribution

It provides a detailed numerical analysis of scalar wave scattering in black hole and wormhole geometries, highlighting differences in scattering patterns.

Findings

Regular black holes have scattering cross sections similar to Schwarzschild black holes.

Wormholes exhibit significantly reduced scattering at large angles for resonant frequencies.

Classical approximations agree well with numerical results within their validity regimes.

Abstract

We study the scattering of monochromatic planar scalar waves in a geometry that interpolates between the Schwarzschild solution, regular black holes and traversable wormhole spacetimes. We employ the partial waves approach to compute the differential scattering cross section of the regular black hole, as well as of the wormhole solutions. We compare our full numerical results with the classical geodesic scattering and the glory approximation, obtaining excellent agreement in the appropriate regime of validity of such approximations. We obtain that the differential scattering cross section for the regular black hole case is similar to the Schwarzschild result. Notwithstanding, the results for wormholes can be very distinctive from the black hole ones. In particular, we show that the differential scattering cross section for wormholes considerably decreases at large scattering angles for resonant frequencies.