Minimumerror discrimination between a pure and a mixed twoqubit state
Abstract
The problem of discriminating with minimum error between two mixed quantum states is reviewed, with emphasis 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 twoqubit states, and the minimum error probabilities achievable by collective and local measurements on the qubits are compared.
 Publication:

Journal of Optics B: Quantum and Semiclassical Optics
 Pub Date:
 March 2004
 DOI:
 10.1088/14644266/6/3/005
 arXiv:
 arXiv:quantph/0307038
 Bibcode:
 2004JOptB...6S..24H
 Keywords:

 minimumerror discriminationmixed statetwoqubit state;
 Quantum Physics
 EPrint:
 6 pages, contribution to the 10th CEWQO, submitted to J. Opt. B