Characteristic Time Scales for the Geometry Transition of a Black Hole to a White Hole from Spinfoams

Understand

Quantum fluctuations of the metric provide a decay mechanism for black holes, through a transition to a white hole geometry.

• Old perplexing results by Ambrus and H\'aj\'i\v{c}ek and more recent results by Barcel\'o, Carballo-Rubio and Garay, indicate a characteristic time scale of this process that scales linearly with the mass of the collapsed object.
• We compute the characteristic time scales involved in the quantum process using Lorentzian Loop Quantum Gravity amplitudes, corroborating these results but reinterpreting and clarifying their physical meaning.
• We first review and streamline the classical set up, and distinguish and discuss the different time scales involved.