Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spontaneous spin bifurcations and ferromagnetic phase transitions in a
  spinor exciton-polariton condensate   We observe a spontaneous parity breaking bifurcation to a ferromagnetic state
in a spatially trapped exciton-polariton condensate. At a critical bifurcation
density under nonresonant excitation, the whole condensate spontaneously
magnetizes and randomly adopts one of two elliptically polarized (up to 95%
circularly-polarized) states with opposite handedness of polarization. The
magnetized condensate remains stable for many seconds at 5 K, but at higher
temperatures it can flip from one magnetic orientation to another. We optically
address these states and demonstrate the inversion of the magnetic state by
resonantly injecting 100-fold weaker pulses of opposite spin. Theoretically,
these phenomena can be well described as spontaneous symmetry breaking of the
spin degree of freedom induced by different loss rates of the linear
polarizations.

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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
1
The categories of this paper are: cs
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: astro-ph
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The categories of this paper are: chem-ph