Minimum-error discrimination between a pure and a mixed two-qubit state

Ulrike Herzog
2004 Journal of Optics B-Quantum and Semiclassical Optics  
The problem of discriminating with minimum error between two mixed quantum states is reviewed, with emphasize on the detection operators necessary for performing the measurement. An analytical result is derived for the minimum probability of errors in deciding whether the state of a quantum system is either a given pure state or a uniform statistical mixture of any number of mutually orthogonal states. The result is applied to two-qubit states, and the minimum error probabilities achievable by
more » ... ties achievable by collective and local measurements on the qubits are compared.
doi:10.1088/1464-4266/6/3/005 fatcat:ry6pwzmymnbz3es2g77adhwjku