Hypothesis testing for an entangled state produced by spontaneous   parametric down conversion
  Generation and characterization of entanglement are crucial tasks in quantum information processing. A hypothesis testing scheme for entanglement has been formulated. Three designs were proposed to test the entangled photon states created by the spontaneous parametric down conversion. The time allocations between the measurement vectors were designed to consider the anisotropic deviation of the generated photon states from the maximally entangled states. The designs were evaluated in terms of the p-value based on the observed data. It has been experimentally demonstrated that the optimal time allocation between the coincidence and anti-coincidence measurement vectors improves the entanglement test. A further improvement is also experimentally demonstrated by optimizing the time allocation between the anti-coincidence vectors. Analysis on the data obtained in the experiment verified the advantage of the entanglement test designed by the optimal time allocation. 
Masahito Hayashi, Bao-Sen Shi, Akihisa Tomita, Keiji Matsumoto,   Yoshiyuki Tsuda, and Yun-Kun Jiang