TOMOGRAPHIC MEASUREMENT OF THE DENSITY-MATRIX OF THE RADIATION-FIELD

Recently a novel homodine tomographic technique has been proposed whic h allows us to detect the density matrix experimentally in terms of av erages on data. The method has been further extended to a general matr ix element (psi/rho/phi) of the density operator rho, along with the p ossibility of using low-efficiency detectors. In this paper this techn ique is reconsidered as a new genuine quantum measurement. Numerical r esults for measured probabilities are given, and the mechanism underly ing the generation of statistical errors in the measured matrix is ill ustrated. It is shown that the data processing of the novel technique can also be used as a new imaging algorithm for conventional tomograph y.