Optimal phase estimation for qubits in mixed states
Giacomo Mauro D’Ariano, Chiara Macchiavello, Paolo Perinotti
We address the problem of optimal estimation of the relative phase for two-dimensional quantum systems in mixed states. In particular, we derive the optimal measurement procedures for an arbitrary number of qubits prepared in the same mixed state.
arXiv:quant-ph/0411133•Physical Review A•Oct 26, 2005•15 citations