Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flat quasiparticle dispersion and a hidden small energy scale in the 2D
  t-J model   A model of weakly interacting hole quasiparticles is proposed to describe the
normal state of the high temperature superconductors. The effect of strong
correlations is contained in the dispersion relation of the holes, which is
obtained accurately using a numerical technique and the t-J model on $12\times
12$ clusters. Saddle-points generated by many-body effects induce quasiparticle
$flat$ bands similar to those observed in recent angle-resolved photoemission
experiments. The near degeneracy between momentum states along the ${\rm X-Y}$
direction is a hidden small energy scale in the problem, which produces a
strongly temperature dependent Hall coefficient, as well as a large Fermi
surface similar to those observed in the cuprates.

6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin