Speaker
Description
Blackbody radiation contains (on average) an entropy of 3.9+-2.5 bits per photon. This applies not only to provervial case of “burning a lump of coal”, but also to the Hawking radiation from black holes. The flip side of this observation is the information budget: If the emission process is unitary, as it certainly is for normal physical burning, then this entropy is exactly compensated by the “hidden information” in the correlations. We shall now extend this argument to the Hawking radiation from black holes, demonstrating that the assumption of unitarity leads to a perfectly reasonable entropy/information budget. The key technical aspect of our calculation is the “average subsystem” approach, but applied to a tripartite pure system consisting of the (black hole)+(Hawking radiation)+(rest of the universe).
Summary
Blackbody radiation contains (on average) an entropy of 3.9+-2.5 bits per photon. This applies not only to provervial case of “burning a lump of coal”, but also to the Hawking radiation from black holes. The flip side of this observation is the information budget: If the emission process is unitary, as it certainly is for normal physical burning, then this entropy is exactly compensated by the “hidden information” in the correlations. We shall now extend this argument to the Hawking radiation from black holes, demonstrating that the assumption of unitarity leads to a perfectly reasonable entropy/information budget. The key technical aspect of our calculation is the “average subsystem” approach, but applied to a tripartite pure system consisting of the (black hole)+(Hawking radiation)+(rest of the universe).
