Can a passing black hole disturbance leave a trace in Hawking radiation?

Key Points:

• Black holes are characterized by just three parameters—mass, charge, and spin—and despite different formation histories, they settle into similar final states, a concept known as "black holes have no hair."
• When quantum effects like Hawking radiation are considered, black holes emit radiation with a temperature related to their surface gravity, but real black holes often experience disturbances that temporarily move them away from a stationary state.
• The study focuses on how temporary directional disturbances affect the redshift of outgoing light rays (described by the peeling field) and how these changes influence the Hawking radiation emitted after the disturbance.
• Using geometric methods and the Borsuk–Ulam theorem, the researchers identify pairs of opposite points on a distorted black hole horizon to measure directional imbalances in the peeling field during disturbances.
• The main result establishes a lower bound on the accumulated deviation of Hawking radiation caused by temporary antipodal imbalances, showing that some variation in radiation is unavoidable even after the disturbance ends, with implications for understanding black hole dynamics beyond idealized stationary conditions.