Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The bulge in the basal plane area of cuprate superconductors - evidence
  for 3a singlet hole pairs   The bulge in the doping dependence of the basal plane area in hole doped
cuprate superconductors is connected with a non-double-occupancy constraint for
the oxygen cages in the CuO_2 lattice. This constraint favors the formation of
3a hole pairs growing to filaments with gapless excitations along the (pi, pi)
direction. Thus in the pseudogap regime a nodal metal of hole pairs is created.
Densest packed 3a hole pairs stabilize the optimum doped state at n =1/6 ~
0.16.

12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ