PRECISION OF QUANTUM TOMOGRAPHIC DETECTION OF RADIATION

Homodyne tomography provides an experimental technique for reconstruct ing the density matrix of the radiation field. Here we analyze the tom ographic precision in recovering observables like the photon number, t he quadrature, and the phase. We show that tomographic reconstruction, despite providing a complete characterization of the state of the fie ld, is generally much less efficient than conventional detection techn iques.