Abstract
This paper explores an application of quantum entanglement. The problem treated here is the quantum channel identification problem: given a parametric family of quantum channels, find the best strategy of estimating the true value of the parameter θ. As a simple example, we study the estimation problem of the isotropic depolarization parameter θ for a two-level quantum system In the framework of noncommutative statistics, it is shown that the optimal input state on to the channel exhibits a transitionlike behavior according to the value of the parameter θ.
- Received 25 August 2000
DOI:https://doi.org/10.1103/PhysRevA.63.042304
©2001 American Physical Society