Entropy, Black Holes, and “Monster” states.
It is generally believed that black holes carry entropy. The need for that isn’t hard to understand: if you throw something into a black hole, its entropy shouldn’t just vanish since this would violate the second law. So an entropy must be assigned to the black hole. More precisely, the entropy is proportional to the surface area of the black holes, since this can be shown to be a quantity which only increases if black holes join, and this is also in agreement with the entropy one derives for a black hole from Hawking radiation. So, black holes have an entropy. But what does that mean? What are the microstates of the black hole? Or where are they? And why doesn’t the entropy depend on what was thrown into the black hole?
[…][I]f you create the monster state and let it evolve in time, it inevitably forms a black hole.