Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optimal signal ensembles   Classical messages can be sent via a noisy quantum channel in various ways,
corresponding to various choices of signal states of the channel. Previous work
by Holevo and by Schumacher and Westmoreland relates the capacity of the
channel to the properties of the signal ensemble. Here we describe some
properties characterizing the ensemble that maximizes the capacity, using the
relative entropy "distance" between density operators to give the results a
geometric flavor.

36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
2
The categories of this paper are: math