Non–Commutative Geometry on Quantum Phase–Space

A non–commutative analogue of the classical differential forms is constructed on the phase–space of an arbitrary quantum system. The non– commutative forms are universal and are related to the quantum mechanical dynamics in the same way as the classical forms are related to classical dynamics. They are constructed by applying the Weyl–Wigner symbol map to the differential envelope of the linear operators on the quantum mechanical Hilbert space. This leads to a representation of the non–commutative forms considered by A. Connes in terms of multiscalar functions on the classical phase–space. In an appropriate coincidence limit they define a quantum deformation of the classical tensor fields and both commutative and non–commutative forms can be studied in a unified framework. We interprete the quantum differential forms in physical terms and comment on possible applications.