Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pi-Josephson Junction and Spontaneous Superflow in Rings from Ultracold
  Fermionic Atomic Gases   he BCS-like pairing in ultracold fermionic atomic ($UCFAG$) gases is studied
in the model of "isotopic-spin" pairing proposed in 1991 \cite% {Ku-Hof-SSC}.
This model assumes a mismatch ($\delta $) in chemical potentials of pairing
fermionic atoms. It is shown that a $\pi $-Josephson junction can be realized
in $UCFAG$ systems, where the left and right banks $% S$ are the $UCFAG$
superfluids. The weak link $M$ consists from the normal $% UCFAG$ with the
finite mismatch $\delta $. If the $\pi $-junction is a part of a closed ring
the superfluid mass-current flows spontaneously in the ring, i.e., the
time-reversal symmetry is broken spontaneously. This is realized if the radius
of the ring $R$ is larger than the critical one $% R_{c} $. All these effects
exist also in the case when $\delta \gg \Delta $, where $\Delta $ is the
superfluid gap, but with the reduced thickness of the weak link. It is also
discussed, that if junctions $SM_{1}M_{2}S$ and trilayers $% M_{1}SM_{2}$ from
$UCFAG$ are realizable this renders a possibility for a novel electronics -
\textit{hypertronics}.

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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: q-bio
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: stat
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The categories of this paper are: comp-gas