Quantum-Corrected Hawking Radiation from Near-Extremal Kerr-Newman Black Holes

Abstract

Near-extremal black holes have a long AdS$_2$ throat in their near-horizon region. Quantum fluctuations in the throat region are effectively governed by a quantum version of Jackiw-Teitelboim gravity with matter and are strongly coupled at low temperatures. We investigate how these quantum fluctuations affect the spectrum of emission of particles during Hawking radiation. We systematically consider the cases of Kerr and Kerr-Newman black holes for emission of scalar particles and discuss photon and graviton emission from the Kerr background. We find that at very low temperatures the quantum fluctuations radically change the nature of particle emission. Unlike the generic suppression of particle emission in the spherically symmetric Reissner-Nordström case, we uncover that for particles with non-vanishing angular momentum, the quantum-corrected emission can be substantially enhanced with respect to the standard semiclassical result.

Figures (13)

• Figure 1: The black hole radiation absorption process that leads to the computation of the greybody factors via spontaneous emission. The near-horizon region is depicted in green anticipating the strong quantum fluctuations that will be incorporated in section \ref{['Sec:Quantum']}.
• Figure 2: Schematic depiction of the black hole absorption process leading to Hawking radiation as spontaneous emission. We emphasize the role of quantum fluctuations in green.
• Figure 3: Comparing the emission, $\frac{dE}{dtd\omega}$, in the quantum-corrected and semi-classical framework for a scalar particle with quantum numbers $s=0, \ell=0, m=0$.
• Figure 4: Comparing the emission rate, $\frac{dE}{dtd\omega}$, in quantum-corrected theory and semi-classical theory for a scalar particle emission with positive angular momentum $s=0$, $\ell=1$, $m=1$ for black hole in classical regime (left) and in quantum regime (right).
• Figure 5: (a) Quantum-corrected and (b) semiclassical emission rates, $\frac{dE}{dtd\omega}$, for $s=0$, $\ell=1$, $m=1$ for the three kinds of black holes in the classical regime $\left( E_{i} \gg E_{\rm brk} \right)$. Inset shows the emission rates for RN black hole, which is much suppressed compared to its rotating cousins.