Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Positive current cross-correlations in a highly transparent
  normal-superconducting beam splitter due to synchronized Andreev and inverse
  Andreev reflections   Predictions are established for linear differential current-current
cross-correlations dSab/dV in a symmetrically biased three-terminal normal
metal-superconductor-normal metal (NSN) device. Highly transparent contacts
turn out to be especially interesting because they feature positive dSab/dV. At
high transparency, processes based on Crossed Andreev Reflection (CAR)
contribute only negligibly to the current and to dSab/dV. Under these
circumstances, current-current cross-correlations can be plausibly interpreted
as a coherent coupling between the two NS interfaces in the form of
synchronized Andreev and inverse Andreev reflections, corresponding to the
process where a pair of electron-like quasi-particles and a pair of hole-like
quasi-particles arrive from the normal electrodes and annihilate in the
superconductor. Hence, positive dSab/dV does not automatically imply CAR. For
tunnel contacts, dSab/dV is positive because of CAR. In between these two
extremities, at intermediate transparencies, dSab/dV is negative because both
processes which cause positive correlations, occur only with small amplitude.
We use scattering theory to obtain analytic expressions for current and noise,
and microscopic calculation using a tight binding model in order to obtain a
clear interpretation of the physical processes.

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The categories of this paper are: nucl-th
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
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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: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-th
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The categories of this paper are: nlin
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The categories of this paper are: supr-con
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The categories of this paper are: q-bio