Greybody factors and quasinormal modes for a nonminimally coupled scalar field in a cloud of strings in (2+1)-dimensional background

TL;DR

This paper analytically investigates how a nonminimally coupled scalar field behaves in a (2+1)-dimensional cloud of strings, revealing detailed properties of scattering, absorption, decay, and stability, with implications for universality.

Contribution

It provides exact analytical expressions for key scattering and decay parameters of a nonminimally coupled scalar in a string cloud background, highlighting the impact of nonminimal coupling.

Findings

Scalar perturbations are stable.

Universality is not generally respected.

Explicit formulas for reflection, absorption, decay, and quasinormal modes.

Abstract

We study the propagation of a probe massless nonminimally coupled scalar field in a fixed gravitational background of a cloud of strings in (2+1) dimensions. We obtain exact analytical expressions for the reflection coefficient, the absorption cross section, the decay rate as well as the quasinormal frequencies. The impact of the nonminimal coupling is investigated in detail. Our results show that Universality is not respected in general, and that scalar perturbations are stable.