Reduction Theorems for Optimal Unambiguous State Discrimination of Density Matrices

Raynal, Philippe; Lütkenhaus, Norbert; van Enk, Steven J.

Reduction Theorems for Optimal Unambiguous State Discrimination of Density Matrices

Authors

Raynal, Philippe

Lütkenhaus, Norbert

van Enk, Steven J.

Description

We present reduction theorems for the problem of optimal unambiguous state discrimination (USD) of two general density matrices. We show that this problem can be reduced to that of two density matrices that have the same rank $n$ and are described in a Hilbert space of dimensions $2n$. We also show how to use the reduction theorems to discriminate unambiguously between N mixed states (N \ge 2).
6 pages, 1 figure