Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-Orders-of-Magnitude Improvement in the Total Spin Angular Momentum
  of 131Xe Nuclei Using Spin Exchange Optical Pumping   We report on hyperpolarization of quadrupolar (I=3/2) 131Xe via spin-exchange
optical pumping. Observations of the 131Xe polarization dynamics show that the
effective alkali-metal/131Xe spin-exchange cross-sections are large enough to
compete with 131Xe spin relaxation. 131Xe polarization up to 7.6 p/m 1.5
percent was achieved in ca. 8.5EE20 spins--a ca. 100-fold improvement in the
total spin angular momentum--enabling applications including measurement of
spin-dependent neutron-131Xe s-wave scattering and sensitive searches for
time-reversal violation in neutron-131Xe interactions beyond the Standard
Model.

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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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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: cs
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: astro-ph