Information-Disturbance Tradeoff in Estimating the Unknown Three-Qubit GHZ State
Zhang Sheng-Li, Xu‐Bo Zou, Ke Li, Chenhui Jin, Guo Guang-Can · Chinese Physics Letters · 2007
In a recent paper, Sacchi (Phys. Rev. Lett. 96 (2006) 220502) studied the information-disturbance tradeoff in estimating an unknown two-qubit maximally entangled state. In this study, we explore the tradeoff in estimating an unknown three-qubit GHZ state. The optimal estimation process supplies a fidelity of (13/54) and the tradeoff interpolates smoothly between non-informative measurement and optimal estimation process.