Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A new boson-fermion model of superconductivity   It is shown that the superconducting energy gap necessarily lead to the
disappearance of some quasi-electrons, thus we suggest a new boson-fermion
Hamiltonian to describe superconductivity. The new supercurrent equations are
derived with this Hamiltonian. Some new results can be found besides the zero
resistance effect, the Meissner effect and the magnetic flux quantum can be
explained.

6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph