Near-Extremal Charged Black Holes: Greybody Factors and Evolution

TL;DR

This paper investigates the quantum effects on the thermodynamics and radiation of near-extremal charged black holes using AdS$_2$/CFT$_1$ correspondence, revealing how greybody factors and evolution are affected at low temperatures.

Contribution

It introduces a calculation of greybody factors including quantum effects for near-extremal charged black holes and analyzes their stochastic evolution and implications for primordial black holes.

Findings

Greybody factors scale as T^{2s + 3/2} at low temperatures.

Hawking radiation is dominated by scalar particles, including the Higgs boson.

Lighter NEBHs have a temperature below the mass gap, around tens of GeV.

Abstract

As a charged black hole reaches its extremal state via Hawking radiation, quantum effects become important for its thermodynamic properties when its temperature is below a mass gap scale. Using AdS$_2$/CFT$_1$ correspondence and solutions for the corresponding Schwarzian action, we calculate the black hole greybody factors including the quantum effects. In the low temperature limit, the greybody factors scale as $T^{2s + 3/2}$ with $s$ the radiated field spin. Hence, the Hawking radiation of a near-extremal charged black hole (NEBH) is dominated by emitting scalar particles including the Higgs boson. Time evolution of an NEBH is also calculated and shows a stochastic feature. For an NEBH lighter than around $10^8$ times the Planck mass, its temperature at the current universe is below the mass gap scale and is universally tens of GeV, which is important if one searches for primordial (hidden) charged black holes.