On the effect of scalar fields on Hawking radiation and quasinormal modes of black holes

Abstract: The present thesis attempts to study the effect of scalar fields on Hawking radiation and quasinormal modes of black holes. We selected a static, spherically symmetric electrically charged black hole with an additional scalar 'hair' for our analysis. The scalar 'hair' is sourced by a scalar field, conformally coupled to the Einstein-Hilbert action. The scalar field can survive even in the absence of the black hole's electric charge and is characterized as a 'primary hair'. This scalar field changes the gravitational constant, and hence modifies the ADM (Arnowitt-Deser-Missner) mass of the black hole. The scalar field's strength is determined by a scalar 'charge' that manifests itself as an additive correction to the square of the electric charge in the standard Reissner-Nordstr\"{o}m metric. This seemingly simple modification leads to nontrivial physical implications.