Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superfluid density and microwave conductivity of FeSe superconductor:
  ultra-long-lived quasiparticles and extended s-wave energy gap   FeSe is an iron-based superconductor of immense current interest due to the
large enhancements of Tc that occur when it is pressurized or grown as a single
layer on an insulating substrate. Here we report precision measurements of its
superconducting electrodynamics, at frequencies of 202 and 658 MHz and at
temperatures down to 0.1 K. The quasiparticle conductivity reveals a rapid
collapse in scattering on entering the superconducting state that is strongly
reminiscent of unconventional superconductors such as cuprates, organics and
the heavy fermion material CeCoIn5. At the lowest temperatures the
quasiparticle mean free path exceeds 50 micron, a record for a compound
superconductor. From the superfluid response we confirm the importance of
multiband superconductivity and reveal strong evidence for a finite energy-gap
minimum.

25
The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ