Narrow resonances and black-hole-like absorption in a non-black-hole metric

TL;DR

This paper shows that a non-black-hole body with a specific interior metric exhibits black-hole-like absorption features, including a dense spectrum of narrow resonances and infinite cross sections as it approaches a critical radius.

Contribution

It demonstrates that a non-black-hole object can display black-hole-like absorption properties through quantum scattering resonances near a critical radius.

Findings

Dense spectrum of narrow resonances appears as the radius approaches the critical value.

Resonance density and lifetimes tend to infinity at the critical radius.

The cross section for particle capture becomes infinite at the critical radius.

Abstract

A massive body with the Schwarzschild interior metric (perfect fluid of constant density) develops a pressure singularity at the origin when the radius of the body $R$ approaches $9r_s/8$, where $r_s$ is the Schwarzschild radius. We show that a quantum scalar particle scattered in this gravitational field possesses a dense spectrum of narrow resonances. Their density and lifetimes tend to infinity in the limit $R\rightarrow 9r_s/8$, and we determine the cross section of the particle capture into these quasibound states. Therefore, a body that is not a black hole demonstrates black-hole-like absorption.