  The root estimator of quantum states based on the expansion of the psi
function in terms of system eigenfunctions followed by estimating the expansion
coefficients by the maximum likelihood method is considered. In order to
provide statistical completeness of the analysis, it is necessary to perform
measurements in mutually complementing experiments (according to the Bohr
terminology). Estimation of quantum states by the results of coordinate,
momentum, and polarization (spin) measurements is considered.
