Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory for charge and orbital density-wave states in manganite
  La$_{0.5}$Sr$_{1.5}$MnO$_4$   We investigate the high temperature phase of layered manganites, and
demonstrate that the charge-orbital phase transition without magnetic order in
La$_{0.5}$Sr$_{1.5}$MnO$_4$ can be understood in terms of the density wave
instability. The orbital ordering is found to be induced by the nesting between
segments of Fermi surface with different orbital characters. The simultaneous
charge and orbital orderings are elaborated with a mean field theory. The
ordered orbitals are shown to be $d_{x^2-y^2} \pm d_{3z^2-r^2}$.

1
The categories of this paper are: cs
2
The categories of this paper are: math
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph