



01645nas a2200205   4500008004100000245008200041210006900123260001500192300001100207490000700218520102200225100001501247700002401262700002101286700001701307700001601324700002701340700001701367856005501384       2016                        eng d00aOptimized tomography of continuous variable systems using excitation counting0 aOptimized tomography of continuous variable systems using excita  c2016/11/21  a0523270 v943 a<p><span style="color: rgb(34, 34, 34); font-family: &quot;Helvetica Neue&quot;, Helvetica, Roboto, Arial, sans-serif; font-size: 14px;">We propose a systematic procedure to optimize quantum state tomography protocols for continuous variable systems based on excitation counting preceded by a displacement operation. Compared with conventional tomography based on Husimi or Wigner function measurement, the excitation counting approach can significantly reduce the number of measurement settings. We investigate both informational completeness and robustness, and provide a bound of reconstruction error involving the condition number of the sensing map. We also identify the measurement settings that optimize this error bound, and demonstrate that the improved reconstruction robustness can lead to an order-of-magnitude reduction of estimation error with given resources. This optimization procedure is general and can incorporate prior information of the unknown state to further simplify the protocol.</span></p>1 aShen, Chao1 aHeeres, Reinier, W.1 aReinhold, Philip1 aJiang, Luyao1 aLiu, Yi-Kai1 aSchoelkopf, Robert, J.1 aJiang, Liang  uhttp://link.aps.org/doi/10.1103/PhysRevA.94.052327