Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Slave-boson field fluctuation approach to the extended Falicov-Kimball
  model: charge, orbital, and excitonic susceptibilities   Based on the SO(2)-invariant slave-boson scheme, the static charge, orbital,
and excitonic susceptibilities in the extended Falicov-Kimball model are
calculated. Analyzing the phase without long-range order we find instabilities
towards charge order, orbital order, and the excitonic insulator (EI) phase.
The instability towards the EI is in agreement with the saddle-point phase
diagram. We also evaluate the dynamic excitonic susceptibility, which allows
the investigation of uncondensed excitons. We find qualitatively different
features of the exciton dispersion at the semimetal-EI and at the
semiconductor-EI transition supporting a crossover scenario between a BCS-type
electron-hole condensation and a Bose-Einstein condensation of preformed bound
electron-hole pairs.

37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ