Stochastic resonance
Stochastic resonance (SR) is a mathematical mechanism and behavior of nonlinear systems (that is, systems in which the change of the output is not proportional to the change of the input) where random (stochastic) fluctuations in the microstate of a system (that is, its specific configuration, including the precise positions and momenta of all its individual particles or components) cause deterministic (that is, non-random) changes in a macrostate (that is, a subset of the system's microstates). This occurs when the nonlinear nature of the system amplifies certain (resonant) portions of the fluctuations, while not amplifying other portions of the noise.