Lecture 12: The second law and the Raychaudhuri Equation
In Lecture 12, we started to investigate the limits of energy extraction from black holes. We found that positivity of local energy in the ergosphere prevented processes that could decrease the area of the black hole. We then started a derivation of a more general version of the second law of thermodynamics. The main technical input required for this derivation is the "Raychaudhuri equation", and we derived this equation.
