Area, ladder symmetry, degeneracy and fluctuations of a horizon

TL;DR

This paper explores the spectrum and degeneracy of quantum horizon areas in loop quantum gravity, revealing harmonic modes that could produce observable bright lines in black hole radiation.

Contribution

It introduces a universal reformulation of the area spectrum with fewer parameters and analyzes the physical fluctuations and harmonic modes of quantum horizons.

Findings

Complete area spectrum as union of equidistant subsets

Identification of harmonic modes with potential observational signatures

Quantum amplification effects leading to bright lines in Hawking radiation

Abstract

Loop quantum gravity admits a kind of area quantization that is characterized by three quantum numbers. We show the complete spectrum of area is the union of equidistant subsets and a universal reformulation with fewer parameters is possible. Associated with any area there is also another number that determines its degeneracy. One application is that a quantum horizon manifests harmonic modes in vacuum fluctuations. It is discussed the physical fluctuations of a space-time horizon should include all the excluded area eigenvalues, where quantum amplification effect occurs. Due to this effect the uniformity of transition matrix elements between near levels could be assumed. Based on these, a modification to the previous method of analyzing the radiance intensities in hep-th/0607081 is presented that makes the result one step further precise. A few of harmonic modes appear to be extremely amplified on top of the Hawking's radiation. They are expected to form a few brightest lines with the wavelength not larger than the black hole size.