Scalar absorption: Black holes versus wormholes

TL;DR

This paper investigates how massless scalar waves are absorbed differently by black holes and wormholes, revealing distinctive spectral features and resonances that could help distinguish these objects.

Contribution

It introduces a unified analysis of scalar wave absorption in geometries interpolating between black holes and wormholes, highlighting unique spectral signatures.

Findings

Black holes and wormholes have distinct absorption spectra.

Wormholes exhibit quasibound states causing Breit-Wigner resonances.

Absorption cross sections vary significantly across the interpolation.

Abstract

We study the absorption of massless scalar waves in a geometry that interpolates between the Schwarzschild solution and a wormhole that belongs to the Morris-Thorne class of solutions. In the middle of the interpolation branch, this geometry describes a regular black hole. We use the partial wave approach to compute the scalar absorption cross section in this geometry. Our results show that black holes and wormholes present distinctive absorption spectra. We conclude, for instance, that the wormhole results are characterized by the existence of quasibound states which generate Breit-Wigner-like resonances in the absorption spectrum.