Planckian physics comes into play at Planckian distance from horizon

In the background of a gravitational collapse, we compute the transition amplitudes for the creation of particles for distant observers due to higher-derivative interactions in addition to Hawking radiation. The amplitudes grow exponentially with time and become of order 1 when the collapsing matter is about a Planck length outside the horizon. As a result, the effective theory breaks down at the scrambling time, invalidating its prediction of Hawking radiation. Planckian physics comes into play to decide the fate of black-hole evaporation.

Automated summary

In the context of a gravitational collapse, the transition amplitudes for the creation of particles due to higher-derivative interactions were computed, revealing that these amplitudes grow exponentially with time and peak when the collapsing matter is approximately a Planck length away from the horizon, leading to the breakdown of the effective theory at the scrambling time. This invalidates its prediction of Hawking radiation, allowing Planckian physics to influence the fate of black hole evaporation.