Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An unknown story: Majorana and the Pauli-Weisskopf scalar
  electrodynamics   An account is given of an interesting but unknown theory by Majorana
regarding scalar quantum electrodynamics, elaborated several years before the
known Pauli-Weisskopf theory. Theoretical calculations and their interpretation
are given in detail, together with a general historical discussion of the main
steps towards the building of a quantum field theory for electrodynamics. A
possible peculiar application to nuclear constitution, as conceived around
1930, considered by Majorana is as well discussed.

37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas