Massive complex scalar field in the Kerr-Sen geometry: Exact solution of wave equation and Hawking radiation

TL;DR

This paper derives an exact solution for the wave equation of a massive complex scalar field in Kerr-Sen geometry and investigates Hawking radiation, showing it shares thermal characteristics with Kerr-Newman black holes.

Contribution

It provides an exact analytical solution to the scalar wave equation in Kerr-Sen spacetime and analyzes Hawking radiation using the Damour-Ruffini-Sannan method.

Findings

Wave equation reduces to a confluent Heun equation.

Hawking radiation in Kerr-Sen black holes is thermally similar to Kerr-Newman.

Exact solutions facilitate understanding of scalar fields in complex black hole geometries.

Abstract

The separated radial part of a massive complex scalar wave equation in the Kerr- Sen geometry is shown to satisfy the generalized spheroidal wave equation which is, in fact, a confluent Heun equation up to a multiplier. The Hawking evaporation of scalar particles in the Kerr-Sen black hole background is investigated by the Damour-Ruffini-Sannan method. It is shown that quantum thermal effect of the Kerr-Sen black hole has the same character as that of the Kerr-Newman black hole.