Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generalized Crossover in Interacting Fermions within the Low-Energy
  Expansion   We generalize the Bardeen-Cooper-Schrieffer-Bose-Einstein-condensation
(BCS-BEC) crossover of two-component fermions, which is realized by tuning the
$s$-wave scattering length $a$ between the fermions, to the case of an
arbitrary effective range $r_{\rm e}$. By using the Nozi\`{e}res-Schmitt-Rink
(NSR) approach, we show another crossover by changing $r_{\rm e}$ and present
several similarities and differences between these two crossovers. Furthermore,
the region ($r_{\rm e}>a/2$) where the effective range expansion breaks down
and the Hamiltonian becomes non-Hermitian is found, being consistent with the
Wigner's causality bound. Our results are universal for low-density interacting
fermions with low-energy constants $a$ and $r_{\rm e}$ and are directly
relevant to ultracold Fermi atomic gases as well as dilute neutron matter.

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The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an