Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Physical accessibility of non-completely positive maps   Maps that are not completely positive (CP) are often useful to describe the
dynamics of open systems. An apparent violation of complete positivity can
occur because there are prior correlations of the principal system with the
environment, or if the applied transformation is correlated with the state of
the system. We provide a physically motivated definition of accessible non-CP
maps and derive two necessary conditions for a map to be accessible. We also
show that entanglement between the system and the environment is not necessary
to generate a non-CP dynamics. We describe two simple approximations that may
be sufficient for some problems in process tomography, and then outline what
these methods may be able to tell us in other situations where non-CP dynamics
naturally arise.

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The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
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The categories of this paper are: nlin
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
1
The categories of this paper are: cs