Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Method for Measurement of Spin-Spin Couplings with sub-mHz Precision
  Using Zero- to Ultralow-Field Nuclear Magnetic Resonance   We present a method which allows for the extraction of physical quantities
directly from zero- to ultralow-field nuclear magnetic resonance (ZULF NMR)
data. A numerical density matrix evolution is used to simulate ZULF NMR spectra
of several molecules in order to fit experimental data. The method is utilized
to determine the indirect spin-spin couplings ($J$-couplings) in these, which
is achieved with precision of $10^{-2}$--$10^{-4}$ Hz. The simulated and
measured spectra are compared to earlier research. Agreement and precision
improvement for most of the $J$-coupling estimates are achieved. The
availability of an efficient, flexible fitting method for ZULF NMR enables a
new generation of precision-measurement experiments for spin-dependent
interactions and physics beyond the Standard Model.

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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-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: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an