Nonexistence of time-periodic solutions of the Dirac equation in nonextreme Kerr-Newman-AdS spacetime

TL;DR

This paper proves the nonexistence of nontrivial, normalizable Dirac particles outside the horizon in non-extreme Kerr-Newman-AdS spacetime, extending spectral analysis results and showing particles must either fall into the black hole or escape.

Contribution

It establishes new nonexistence results for Dirac solutions in Kerr-Newman-AdS spacetime using spectral methods, generalizing previous findings for the case Q=0.

Findings

No nontrivial Dirac particles with certain $L^p$ properties outside the horizon.

Massive Dirac particles with mass > $rac{ ext{ extbackslash}kappa$ cannot exist outside the horizon.

Particles with eigenvalue $||<rac{ ext{ extbackslash}kappa$ must be $L^2$ outside the horizon.

Abstract

In non-extreme Kerr-Newman-AdS spacetime, we prove that there is no nontrivial Dirac particle which is $L^p$ for $0<p\leq\frac{4}{3}$ with arbitrary eigenvalue $\lambda$, and for $\frac{4}{3}<p\leq\frac{4}{3-2q}$, $0<q<\frac{3}{2}$ with eigenvalue $|\lambda|>q \kappa $, outside and away from the event horizon. By taking $q=\frac{1}{2}$, we show that there is no normalizable massive Dirac particle with mass greater than $\frac{\kappa}{2} $ outside and away from the event horizon in non-extreme Kerr-Newman-AdS spacetime, and they must either disappear into the black hole or escape to infinity, and this recovers the same result of Belgiorno and Cacciatori in the case of $Q=0$ obtained by using spectral methods. Furthermore, we prove that any Dirac particle with eigenvalue $|\lambda|<\frac{\kappa}{2}$ must be $L^2$ outside and away from the event horizon.