Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Achievable Rates of Multidimensional Rotationally Invariant
  Distributions   The maximum achievable rate or mutual informa- tion of multidimensional
rotationally invariant distributions in the presence of additive white Gaussian
noise is analyzed. A simple expression for the special case of multisphere
distributions is derived. Such distributions consist of points in a
multidimensional Euclidean space that are uniformly distributed over several
multidimensional concentric hyperspheres. For the 2-dimensional case, such
distributions have been previously considered in order to reduce the
computational complexity of finding a bound on the channel capacity of
fiber-optic channels. These distributions take advantage of the statistical
rotational invariance of the noise and nonlinear distortions in fiber-optic
channels. Using the derived mutual information expression, 2- and 4-dimensional
multisphere distributions are compared for fiber-optic dual-polarization
channels dominated by linear noise. At high signal-to-noise ratios,
4-dimensional multisphere distributions offer higher achievable rates than
2-dimensional ones transmitted on each of the two polarizations of the optical
carrier. Such 4-dimensional multisphere distributions are also shown to be
statistically invariant under 4-dimensional nonlinear transmission in fibers.

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The categories of this paper are: ao-sci
3
The categories of this paper are: physics
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The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
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The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph