Decoding infrared imprints of quantum origins of black holes

Understand

We analyze the emission spectrum of a (fundamentally quantum) black hole in the Kerr-Newman family by assuming a discretization of black hole geometry and the holographic entropy-area relation.

• We demonstrate that, given the above structure of black hole entropy, a macroscopic black hole always has non-continuously separated mass states and therefore they descend down in discrete manner.
• We evaluate the step size of the discrete spectrum, which vanishes in the extremal limit, leading to a continuum spectrum as expected from thermal nature of black holes.
• This further reveals an interesting relation, in each class, between the dynamic and kinematic length scales for all black holes belonging to the Kerr-Newman family, pointing towards a possible universal character across the class, dependent only on black hole mass.