Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Improved Composite-Boson Theory of Quantum Hall Ferromagnets and
  Skyrmions without Sigma Models   We propose an improved composite-boson theory of quantum Hall ferromagnets,
where the field operator describes solely the physical degrees of freedom
representing the deviation from the ground state. In this scheme skyrmions
appear merely as generic excitations confined in the lowest Landau level. We
evaluate the excitation energy of one skyrmion. Our theoretical estimation
accounts for the activation-energy data due to Schmeller et al. remarkably
well.

10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys