Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bulk viscosities for cold Fermi superfluids close to the unitary limit   We compute the coefficients of bulk viscosity for a non-relativistic
superfluid corresponding to a fermionic system close to the unitarity limit. We
consider the low temperature regime assuming that the transport properties of
the system are dominated by phonons. To compute the coefficients of bulk
viscosity we use kinetic theory in the relaxation time approximation and the
low energy effective field theory of the corresponding system. We show that the
three independent bulk viscosity coefficients, $\zeta_1, \zeta_2, \zeta_3$,
associated with irreversible flows vanish for phonons with a linear dispersion
law. Considering a phonon dispersion law with a cubic term in momentum we find
that in the conformal limit $\zeta_1 = \zeta_2=0$, while $\zeta_3$ is non-zero.
Including a conformal breaking term which arises for a large but finite s-wave
scattering length, $a$, at the leading order in $1/a$ we obtain that $\zeta_1
\propto 1/a$ and $\zeta_2 \propto 1/a^2$.

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The categories of this paper are: nlin
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: astro-ph
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The categories of this paper are: cs