Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the minimum number of unitaries needed to describe a random-unitary
  channel   We provide, in an extremely simple way, an upper bound to the minimum number
of unitary operators describing a general random-unitary channel.

12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga