A complete solution to the problem of setting up Wigner distribution for
N-level quantum systems is presented. The scheme makes use of some of the ideas
introduced by Dirac in the course of defining functions of noncommuting
observables and works uniformly for all N. Further, the construction developed
here has the virtue of being essentially input-free in that it merely requires
finding a square root of a certain N^2 x N^2 complex symmetric matrix, a task
which, as is shown, can always be accomplished analytically. As an
illustration, the case of a single qubit is considered in some detail and it is
shown that one recovers the result of Feynman and Wootters for this case
without recourse to any auxiliary constructs.Comment: 14 pages, typos corrected, para and references added in introduction,
submitted to Jour. Phys.
