Bargmann-Wigner Formulation and Superradiance Problem of Bosons and Fermions in Kerr Space-time

TL;DR

This paper investigates superradiance phenomena of bosons and fermions in Kerr spacetime using the Bargmann-Wigner formulation, revealing conditions under which superradiance occurs or is suppressed.

Contribution

It provides a unified description of bosonic and fermionic superradiance in Kerr spacetime through the Bargmann-Wigner equations, clarifying when superradiance can or cannot occur.

Findings

Superradiance with positive energy and negative horizon momentum does not occur.

Superradiance with negative energy and positive horizon momentum is possible for both bosons and fermions.

Bargmann-Wigner formulation links fermionic and bosonic superradiance phenomena.

Abstract

The superradiance phenomena of massive bosons and fermions in the Kerr spacetime are studied in the Bargmann-Wigner formulation. In case of bi-spinor, the four independent components spinors correspond to the four bosonic freedom: one scalar and three vectors uniquely. The consistent description of the Bargmann-Wigner equations between fermions and bosons shows that the superradiance of the type with positive energy $(0<\omega)$ and negative momentum near horizon $(p_{\rm H}<0)$ is shown not to occur. On the other hand, the superradiance of the type with negative energy $(\omega<0)$ and positive momentum near horizon $(0<p_{\rm H})$ is still possible for both scalar bosons and spinor fermions.