Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A quantum mechanism underlying the gauge symmetry in quantum
  electrodynamics   In this paper, a formulation, which is completely established on a quantum
ground, is presented for basic contents of quantum electrodynamics (QED). This
is done by moving away, from the fundamental level, the assumption that the
spin space of bare photons should (effectively) possess the same properties as
those of free photons observed experimentally. Within this formulation, bare
photons with zero momentum can not be neglected when constructing the photon
field; and an explicit expression for the related part of the photon field is
derived. When a local gauge transformation is performed on the electron field,
this expression predicts a change that turns out to be equal to what the gauge
symmetry requires for the gauge field. This gives an explicit mechanism, by
which the photon field may change under gauge transformations in QED.

10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph