Multi-photon system has been studied by many groups, however the biggestchallenge faced is the number of copies of an unknown state are limited and farfrom detecting quantum entanglement. The difficulty to prepare copies of thestate is even more serious for the quantum state tomography. One possible wayto solve this problem is to use adaptive quantum state tomography, which meansto get a preliminary density matrix in the first step and revise it in thesecond step. In order to improve the performance of adaptive quantum statetomography, we develop a new distribution scheme of samples and extend it tothree steps, that is to correct it once again based on the density matrixobtained in the traditional adaptive quantum state tomography. Our numericalresults show that the mean square error of the reconstructed density matrix byour new method is improved to the level from $10^{-4}$ to $10^{-9}$ for severaltested states. In addition, PhaseLift is also applied to reduce the requiredstorage space of measurement operator.
展开▼
