Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Doping of a spin-1 chain: integrable model   An exactly soluble model describing a spin S=1 antiferromagnetic chain doped
with mobile S=1/2 carriers is constructed. In its continuum limit the undoped
state is described by three gapless Majorana fermions composing the SU(2)
triplet. Doping adds to this a scalar charge field and a singlet Majorana
fermion with different velocity. We argue that this mode survives when the
Haldane gap is added.

7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat