Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Majorana fermions in superconducting nanowires without spin-orbit
  coupling   We show that confined Majorana fermions can exist in nanowires with proximity
induced s-wave superconducting pairing if the direction of an external magnetic
field rotates along the wire. The system is equivalent to nanowires with
Rashba-type spin-orbit coupling, with strength proportional to the derivative
of the field angle. For realistic parameters, we demonstrate that a set of
permanent magnets can bring a nearby nanowire into the topologically
non-trivial phase with localized Majorana modes at its ends. Without the
requirement of spin-orbit coupling this opens up for a new route for
demonstration and design of Majorana fermion systems.

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The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: astro-ph
3
The categories of this paper are: physics
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int