  Very recently we present a theory [Wei-long She, Chin. Phys. 14, 2514(2005);
Online: http://www.jop.org/journals/cp; http://arxiv.org/abs/quant-ph/0512097]
to show that the quantization of light energy in vacuum can be derived directly
from classical electromagnetic theory through the consideration of statistics
based on classical physics and reveal that the quantization of energy is an
intrinsic property of light as a classical electromagnetic wave and has no need
of being related to particles. In this theory a key concept of stability of
statistical distribution was involved. Here is a note to the theory, which
would be helpful for understanding the concept of stability of statistical
distribution.
