The phenomena of radiation reaction is widely considered the oldest problem in physics. This recoil, or reaction, experienced by radiation emission has not only been plagued with theoretical paradoxes, but has also remained outside the realm of experimental investigation for over a century. However, a recent series of high energy channeling experiments carried out by the NA63 collaboration at CERN have finally brought about the first observations and insights into the nature of radiation reaction. One of the key insights from these measurements comes from the enormous acceleration produced by the recoil, which is so strong that it causes the system to thermalize. These highly accelerated systems will have an associated Rindler horizon which produces Unruh radiation at the celebrated Fulling-Davies-Unruh (FDU) temperature. The emission and absorption of this Unruh radiation will not only affect the Rindler horizon in accordance with the Bekenstein-Hawking area-entropy law, but will also imprint the FDU temperature on the channeling radiation itself. As such, I will discuss these various aspects of thermalized radiation reaction recently measured by the NA63 collaboration.
The seminar is based on https://journals.aps.org/prd/abstract/10.1103/PhysRevD.104.025015