Engineers at Washington University in St. Louis have developed mathematical tools that describe the movement in a stochastic (random) system just before it becomes random. The diffusive motion of such systems, called a “random walk,” is found in physical and nonphysical systems.
(For the former, think cattle coming through a gate into a field; for the latter, think “viral” internet postings.) Researchers have long wondered when the randomness sets in. These new tools help to answer that question and will potentially help predict the onset of chaos in everything from nanoparticles to stock price fluctuations.