Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electron interaction with the angular momentum of the electromagnetic
  field   We give a simple derivation and explanation of a recently proposed new
relativistic interaction between the electron and the angular momentum of the
electromagnetic field in quantum electrodynamics (QED). Our derivation is based
on the work of Moller, who pointed out that, in special relativity, a particle
with spin must always have a finite extension. We generalize Mollers classical
result to the quantum regime and show that it leads to a new contribution to
the energy, which is the special relativistic interaction term. In addition, we
show that all spin terms arising from the Dirac equation may be obtained by
this method.

34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn