Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pairing via Index theorem   This work is motivated by a specific point of view: at short distances and
high energies the undoped and underdoped cuprates resemble the $\pi$-flux phase
of the t-J model. The purpose of this paper is to present a mechanism by which
pairing grows out of the doped $\pi$-flux phase. According to this mechanism
pairing symmetry is determined by a parameter controlling the quantum tunneling
of gauge flux quanta. For zero tunneling the symmetry is $d_{x^2-y^2}+id_{xy}$,
while for large tunneling it is $d_{x^2-y^2}$. A zero-temperature critical
point separates these two limits.

28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex