title: Distribution function in quantal cumulant dynamics.
abstract: We have derived a quantum distribution function in terms of cumulants that are expectation values of a (anti)symmetric-ordered product of position and momentum fluctuation operators. A second-order approximation leads a Gaussian distribution function, which is positive definite and has proper marginals so that the Shannon entropy can be evaluated.
authors.affiliation: Department of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Ibaraki 305-8571, Japan. shigeta@comas.frsc.tsukuba.ac.jp
authors.forename: Yasuteru
authors.initials: Y
authors.lastname: Shigeta