Lecture 4: Hawking radiation
In this lecture, we derived the form of Hawking radiation both in asymptotically flat space and in AdS. This result follows immediately when one puts together the results of previous lectures on (a) the universal entanglement of local degrees of freedom across a null surface and on (b) the mode-expansion of a quantum field in the black-hole geometry. Physically, the phenomenon of Hawking radiation follows from a combination of short-distance physics --- which implies that certain local-degrees of freedom near the black-hole horizon are thermally occupied --- and the late-time isometry of the geometry that allows us to relate these near-horizon degrees of freedom to global modes.
