Optimal quantum state estimation with use of the no-signaling principle
Yeong Deok Han, Joonwoo Bae, Xiang‐Bin Wang, Won-Young Hwang · Physical Review A · 2010
A simple derivation of the optimal state estimation of a quantum bit was obtained by using the no-signaling principle. In particular, the no-signaling principle determines a unique form of the guessing probability independent of figures of merit, such as the fidelity or information gain. This proves that the optimal estimation for a quantum bit can be achieved by the same measurement for almost all figures of merit.