Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin in fractional quantum Hall systems   A system at filling factor 2/3 could be a candidate for a quantum Hall
ferromagnet at integer filling factor of composite fermions. Using exact
diagonalization with electrons on a torus we study the transition from the
singlet ground state to the polarized ground state at this filling and look for
signatures of quantum Hall ferromagnetism. Differences between the fractional
and corresponding integer systems are emphasised. Most interestingly, we find
around the transition a low excited half-polarized state which might become the
ground state in the thermodynamical limit. We study its structure and compare
it to the singlet and polarized ground states. A new interpretation of the
singlet state is suggested and comparison of the filling factors 2/3 and 2/5 is
presented. Adding magnetic inhomogeneities into the system we investigate the
stability of all the three involved states and the tendency to build up domains
like in conventional ferromagnets.

29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph