Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for Point Nodes in the Superconducting Gap Function in the
  Filled Skutterudite Heavy-Fermion Compound PrOs4Sb12: 123Sb-NQR Study under
  Pressure   We report $^{123}$Sb nuclear quadrupole resonance (NQR) measurements of the
filled skutterudite heavy-fermion superconductor PrOs$_4$Sb$_{12}$ under high
pressures of 1.91 and 2.34 GPa. The temperature dependence of NQR frequency and
the spin-lattice relaxation rate $1/T_1$ indicate that the
crystal-electric-field splitting $\Delta_{\rm CEF}$ between the ground state
$\Gamma_1$ singlet and the first excited state $\Gamma_4^{(2)}$ triplet
decreases with increasing pressure. The 1/$T_1$ below $T_c$ = 1.55 K at $P$ =
1.91 GPa shows a power-law temperature variation and is proportional to $T^5$
at temperatures considerably below $T_c$, which indicates the existence of
point nodes in the superconducting gap function. The data can be well fitted by
the gap model $\Delta(\theta)=\Delta_0\sin\theta$ with $\Delta_0$ = 3.08$k_{\rm
B}T_{\rm c}$. The relation between the superconductivity and the quadrupole
fluctuations associated with the $\Gamma_4^{(2)}$ state is discussed.

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The categories of this paper are: funct-an
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The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: econ
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc