  We introduce a method of quantum tomography for a continuous variable system
in position and momentum space. We consider a single two-level probe
interacting with a quantum harmonic oscillator by means of a class of
Hamiltonians, linear in position and momentum variables, during a tunable time
span. We study two cases: the reconstruction of the wavefunctions of pure
states and the direct measurement of the density matrix of mixed states. We
show that our method can be applied to several physical systems where high
quantum control can be experimentally achieved.
