ABSTRACT
For systems not in equilibrium, the approach to equilibrium, which is characterized by an increase in entropy, may be understood in terms of the fundamental postulate given in Section 5.1. In equilibrium, all accessible microstates occur with equal probability. is implies that the probability of ˆnding the system in a particular microstate r is p E V Nr = 1/ ( , , )Ω . A system not in equilibrium at some instant will not have equal probabilities for all the accessible microstates. e system will then evolve with time until the probabilities are equal. ese considerations do not, however, provide any information on how long it will take to reach equilibrium.
