Quantum inference of states and processes
Miroslav Ježek, Jaromı́r Fiurášek, Z. Hradil · Physical Review A · 2003
The maximum-likelihood principle unifies inference of quantum states and processes from experimental noisy data. Particularly, a generic quantum process may be estimated simultaneously with unknown quantum probe states, provided that measurements on probe and transformed probe states are available. Drawbacks of various approximate treatments are also considered.