Quantum Kinetics and the Planck Equation

With the same system that Einstein employed, the Planck equation should issue directly from kinetic principles without the aid of the theory of induced emission. The three fundamental laws of physico-chemical kinetics are (1) the law of entire equilibrium, (2) the law of the duality of elementary processes (or the equality of direct and reverse transition probabilities), (3) the law of equal a priori probabilities. It is shown that all three follow from the law of the symmetry of time, and furthermore, that the first and third of these laws are both derivable from the second.From one of these laws, from the equation of Boltzmann, and from the number of quantum positions in a Hohlruam within a given range of frequency, the equation of Planck is immediately derived. Finally, there is a brief discussion of the more general case of thermal equilibrium in a Hohlraum when the number of photons is permanently or temporarily restricted, resulting in a state of gray rather than of black radiation.