Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reduction Theorems for Optimal Unambiguous State Discrimination of
  Density Matrices   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).

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The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
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The categories of this paper are: q-fin
10
The categories of this paper are: q-bio