Endpoint of black hole evaporation

Determine the end state of an evaporating black hole once its mass approaches the Planck scale, specifying what physical process terminates Hawking evaporation and identifying the final products, within a consistent quantum theory of gravity.

Background

After describing the timescale and energetics of Hawking radiation, the notes explain that Hawking’s semiclassical approximation is valid until the black hole mass becomes comparable to the Planck mass. Beyond this point, the approximation breaks down and the dynamics require a full quantum gravity treatment.

The author highlights that while the expectation is that the evaporation eventually ends, there is no established derivation of the final state or mechanism. This unknown concerns the fundamental question of how black holes resolve at the smallest scales and whether they leave behind remnants or purely radiate away into known stable particles.