  The complexity of a system, in general, makes it difficult to determine some
or almost all matrix elements of its operators. The lack of accuracy acts as a
source of randomness for the matrix elements which are also subjected to an
external potential due to existing system conditions. The fluctuation of
accuracy due to varying system-conditions leads to a diffusion of the matrix
elements. We show that, for the single well potentials, the diffusion can be
described by a common mathematical formulation where system information enters
through a single parameter. This further leads to a characterization of
physical properties by an infinite range of single parametric universality
classes.
