Information-disturbance tradeoff in estimating a maximally entangled state.
We derive the amount of information retrieved by a quantum measurement in estimating an unknown maximally entangled state, along with the pertaining disturbance on the state itself. The optimal tradeoff between information and disturbance is obtained, and a corresponding optimal measurement is provided.
Sacchi
Massimiliano F
MF
QUIT Quantum Information Theory Group, Dipartimento di Fisica "A. Volta," via A. Bassi 6, I-27100 Pavia, Italy.