Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Extended Nuclear Quadrupole Resonance Study of the Heavy-Fermion
  Superconductor PuCoGa$_5$   PuCoGa$_5$ has emerged as a prototypical heavy-fermion superconductor, with
its transition temperature ($T_c\simeq18.5$ K) being the highest amongst such
materials. Nonetheless, a clear description as to what drives the
superconducting pairing is still lacking, rendered complicated by the
notoriously intricate nature of plutonium's 5$f$ valence electrons. Here, we
present a detailed $^{69,71}$Ga nuclear quadrupole resonance (NQR) study of
PuCoGa$_5$, concentrating on the system's normal state properties near to $T_c$
and aiming to detect distinct signatures of possible pairing mechanisms. In
particular, the quadrupole frequency and spin-lattice relaxation rate were
measured for the two crystallographically inequivalent Ga sites and for both Ga
isotopes, in the temperature range 1.6 K - 300 K. No evidence of significant
charge fluctuations is found from the NQR observables. On the contrary, the
low-energy dynamics is dominated by anisotropic spin fluctuations with strong,
nearly critical, in-plane character, which are effectively identical to the
case of the sister compound PuCoIn$_5$. These findings are discussed within the
context of different theoretical proposals for the unconventional pairing
mechanism in heavy-fermion superconductors.

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The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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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: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: math
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ph