Introduction to quantum Fisher information

Understand

The subject of this paper is a mathematical transition from the Fisher information of classical statistics to the matrix formalism of quantum theory.

• If the monotonicity is the main requirement, then there are several quantum versions parametrized by a function.
• In physical applications the minimal is the most popular.
• There is a one-to-one correspondence between Fisher informations (called also monotone metrics) and abstract covariances.