Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bound spinons in an antiferromagnetic S=1/2 chain with a staggered field   Inelastic neutron scattering was used to measure the magnetic field
dependence of spin excitations in the antiferromagnetic S=1/2 chain CuCl_2
2(dimethylsulfoxide) (CDC) in the presence of uniform and staggered fields.
Dispersive bound states emerge from a zero-field two-spinon continuum with
different finite energy minima at wave numbers q=pi and q_i approx pi
(1-2<S_z>). The ratios of the field dependent excitation energies are in
excellent agreement with predictions for breather and soliton solutions to the
quantum sine-Gordon model, the proposed low-energy theory for S=1/2 chains in a
staggered field. The data are also consistent with the predicted soliton and
n=1,2 breather polarizations and scattering cross sections.

29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an