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High Energy Theory Group Seminars
Quantum transparency and decoherence of near-extremal black holes
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Europe/Rome
Description
It has recently been understood that the near-horizon geometry of near-extremal black holes undergoes large quantum fluctuations, signaling a breakdown of semiclassical gravity. Remarkably, these large quantum gravity effects are controllable and happen at curvatures far below the Planck scale.
I will describe three ways of probing these large quantum fluctuations. First, black holes sufficiently close to extremality become transparent to low-frequency electromagnetic and gravitational radiation of fixed helicity, due to a spin-induced energy gap that forbids absorption below a frequency threshold. Second, this gap modifies the Danielson–Satishchandran–Wald decoherence effect: the decoherence rate induced by near-extremal black holes on quantum superpositions in their exterior can vanish identically, and even above the gap, coherence exceeds semiclassical predictions. Third, I will discuss the quantum deformability of near-extremal black holes—their quantum Love numbers—as a further probe of this structure.