Optimal, reliable estimation of quantum states

  title={Optimal, reliable estimation of quantum states},
  author={Robin Blume-Kohout},
  journal={New Journal of Physics},
Accurately inferring the state of a quantum device from the results of measurements is a crucial task in building quantum information processing hardware. The predominant state estimation procedure, maximum likelihood estimation (MLE), generally reports an estimate with zero eigenvalues. These cannot be justified. Furthermore, the MLE estimate is incompatible with error bars, so conclusions drawn from it are suspect. I propose an alternative procedure, Bayesian mean estimation (BME). BME never… 

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