Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Meissner effect puzzle and the quantum force in superconductor   The puzzle of the acceleration of the mobile charge carriers and the ions in
the superconductor in direction opposite to the electromagnetic force revealed
formerly in the Meissner effect is considered in the case of the transition of
a narrow ring from normal to superconducting state. It is elucidated that the
azimuthal quantum force was deduced eleven years ago from the experimental
evidence of this acceleration but it can not solve this puzzle. This quantum
force explains other paradoxical phenomena connected with reiterated switching
of the ring between normal and superconducting states.

23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess