Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Physical Picture of Superconductivity   A universal mechanism of superconductivity applicable to ``low temperature''
and ``high temperature'' superconductors is proposed in this paper. With this
model of mechanism experimental facts of superconductors can be qualitatively
explained. A function is introduced to describe the average separation distance
between vibrating lattice atoms, which is crucial for the transition from
normal to superconductive state. However, the most attractive and exciting
conclusion that can be derived from this physical picture, is that given atoms
of other element be successfully sandwiched between ferromagnetic atoms one by
one, a superconductor constructed this way is most likely to have a very high
transition temperature.

26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn