Abstract
Long ago, Moyal [Proc. Cambridge Philos. Soc. 45, 99 (1949)] formulated a moment problem in the context of the Wigner–Weyl phase-space formulation of quantum mechanics. The problem amounts to giving necessary and sufficient conditions for a sequence of numbers to be moments of a Wigner function. In this paper, that problem is solved, and so is a truncated version of it.