# A Matrix Method for Quasinormal Modes: Kerr and Kerr-Sen Black Holes

## TL;DR

This paper introduces a matrix method to accurately and efficiently compute scalar quasinormal modes of Kerr and Kerr-Sen black holes by transforming the perturbation equations into a matrix eigenvalue problem.

## Contribution

The paper presents a novel matrix discretization approach for calculating quasinormal modes of black holes, applicable to Kerr and Kerr-Sen solutions.

## Key findings

- The method accurately computes quasinormal frequencies and angular quantum numbers.
- It demonstrates efficiency in solving the eigenvalue problem for black hole perturbations.
- The approach is validated as a reliable tool for black hole quasinormal mode analysis.

## Abstract

In this letter, a matrix method is employed to study the scalar quasinormal modes of Kerr as well as Kerr-Sen black holes. Discretization is applied to transfer the scalar perturbation equation into a matrix form eigenvalue problem, where the resulting radial and angular equations are derived by the method of separation of variables. The eigenvalues, quasinormal frequencies $\omega$ and angular quantum numbers $\lambda$, are then obtained by numerically solving the resultant homogeneous matrix equation. This work shows that the present approach is an accurate as well as efficient method for investigating quasinormal modes.