Phys.Lett.B, 874, 140245 (2026)
The Upper Bound of Event Horizon Formation Time in Generalized Oppenheimer-Snyder Collapse
Zhi-chao Li1, H. Khodabakhshi1 and Hong Lu1
1 Center for Joint Quantum Studies, Department of Physics, School of Science, Tianjin University, Tianjin 300350, China.
* mrhonglu@gmail.com
Abstract
We prove that, in the framework of the Oppenheimer-Snyder collapse, the Schwarzschild exterior maximizes the event horizon formation time ΔTeh=196m among all asymptotically flat, static, spherically-symmetric black holes with the same ADM mass mm that satisfy the weak energy condition. This bound extends the typical black hole inequalities--such as the Penrose inequality, which constrains spatial geometry--to temporal setting.
