Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scattering resonances and two-particle bound states of the extended
  Hubbard model   We present a complete derivation of two-particle states of the
one-dimensional extended Hubbard model involving attractive or repulsive
on-site and nearest-neighbour interactions. We find that this system possesses
scattering resonances and two families of energy-dependent interaction-bound
states which are not present in the Hubbard model with the on-site interaction
alone.

2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th