Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Conserved Currents of the Maxwell Equations with Electric and Magnetic
  Sources   New Lagrangians, depending on the field strengths and the electric and
magnetic sources are found, which lead to the Maxwell equations. One new
feature is that the equations of motion are obtained by varying the Lagrangian
with respect to both the field strengths and the sources. In this way,
conserved currents can be found for the field strengths and the electric or
magnetic sources. Furthermore, using the equations of motion, the electric or
magnetic sources can be eliminated, leading to conserved currents for the field
strengths only (in the presence of electric and magnetic sources). Another new
feature is the construction of a Lagrangian invariant under the duality
transformation for both field strengths and electric and magnetic sources. The
conserved current, after the elimination of electric and magnetic sources,
depends on the field strengths only. The conserved quantity is related to the
total helicity of the electromagnetic field.

30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc