Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tunneling and Photoemission in an SO(6) Superconductor   Combining the results of tunneling, photoemission and thermodynamic studies,
the pseudogap is unambiguously demonstrated to be caused by Van Hove nesting: a
splitting of the density of states peak at $(\pi, 0)$. The fact that the
splitting remains symmetric about the Fermi level over an extended doping range
indicates that the Van Hove singularity is pinned to the Fermi level. Despite
these positive results, an ambiguity remains as to what instability causes the
pseudogap. Charge or spin density waves, superconducting fluctuations, and flux
phases all remain viable possibilities. This ambiguity arises because the
instabilities of the two-dimensional Van Hove singularity are associated with
an approximate SO(6) symmetry group, which contains Zhang's SO(5) as a
subgroup. It has two 6-component superspins, one of which mixes Zhang's
(spin-density wave plus d-wave superconductivity) superspin with a flux phase
operator. This is the smallest group which can explain striped phases in the
cuprates. Evidence for a prefered hole density in the charged stripes is
discussed.

25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn