Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Borromean ground state of fermions in two dimensions   The study of quantum mechanical bound states is as old as quantum theory
itself. Yet, it took many years to realize that three-body borromean systems
that are bound when any two-body subsystem is unbound are abundant in nature.
Here we demonstrate the existence of borromean systems of spin-polarized
(spinless) identical fermions in two spatial dimensions. The ground state with
zero orbital (planar) angular momentum exists in a borromean window between
critical two- and three-body strengths. The doubly degenerate first excited
states of angular momentum one appears only very close to the two-body
threshold. They are the lowest in a possible sequence of so-called super-Efimov
states. While the observation of the super-Efimov scaling could be very
difficult, the borromean ground state should be observable in cold atomic gases
and could be the basis for producing a quantum gas of three-body states in two
dimensions.

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The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
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The categories of this paper are: eess
37
The categories of this paper are: supr-con
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The categories of this paper are: stat
31
The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
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The categories of this paper are: cs
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
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The categories of this paper are: astro-ph
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The categories of this paper are: solv-int