Speaker
Description
In this talk, I will discuss the formation, detection and coarse-graining of black holes in AdS/CFT, with an emphasis on the tension between boundary unitarity and the production of mixed state Hawking radiation in the bulk. I will construct CFT states dual to black hole formation and evaporation by colliding bulk particle wavepackets at trans-Planckian energy. I will propose boundary probes which are able to distinguish small AdS black holes from other states within the microcanonical ensemble. I will discuss different coarse-graining prescriptions acting on the evolving CFT state, including averaging over CFT data, Hamiltonians and time windows, and compare their purities to those expected from the bulk semiclassical description. These results clarify how semiclassical black hole behaviour can arise from an ensemble-averaging of the exact unitary dynamics, and take a step towards a better understanding of coarse-graining in the single-sided black hole information problem. Based on arXiv:2601.22077 with Jan de Boer and Jildou Hollander.