Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NMR study of the S=1/2 Heisenberg Ladder Cu2(C5H12N2)2Cl4 : Quantum
  phase transition and critical dynamics   We present an extensive NMR study of the spin-1/2 antiferromagnetic
Heisenberg ladder Cu2(C5H12N2)2Cl4 in a magnetic field range 4.5 - 16.7 T. By
measuring the proton NMR relaxation rate 1/T_1 and varying the magnetic field
around the critical field H_c1 = Delta / g\mu_B = 7.5 T, we have studied the
transition from a gapped spin liquid ground state to a gapless magnetic regime
which can be described as a Luttinger liquid. We identify an intermediate
regime T > |H-H_c1|, where the spin dynamics is (possibly) only controlled by
the T=0 critical point H_c1.

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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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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: nucl-ex
0
The categories of this paper are: hep-ph
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The categories of this paper are: nlin
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: econ