Abstract

The root mean square perturbations on particles produced by vacuum radiation must be limited by the uncertainty principle, i.e., <dx²>^? <dp_x²>^? = h/2, where <dx²>^? and <dp_x²>^? are the root mean square values of drift in spatial and momentum coordinates. The value <dx²>^? = (ht/m)^?, where m is the mass of the particle, can be obtained both from classical SED calculation and the stochastic interpretation of quantum mechanics. Substituting the latter result into the uncertainty principle yields a fractional change in momentum coordinate, <dp_x²>^? / p, where p is the total momentum, equal to 2^-3/2 (h/Et)^?, where E is the kinetic energy. It is shown that when an initial change <dp_x²>^? is amplified by the lever arm of a molecular interaction, <dp_x²>^? / p > = 1 in only a few collision times. Therefore the momentum distribution of a collection of interacting particles is randomized in that time, and the action of vacuum radiation on matter can account for entropy increase in thermodynamic systems. The interaction of vacuum radiation with matter is time-reversible. Therefore whether entropy increase in thermodynamic systems is ultimately associated with an arrow of time depends on whether vacuum photons are created in a time-reversible or irreversible process. Either scenario appears to be consistent with quantum mechanics.