Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electron-positron pair oscillation in spatially inhomogeneous electric
  fields and radiation   It is known that strong electric fields produce electron and positron pairs
from the vacuum, and due to the back-reaction these pairs oscillate back and
forth coherently with the alternating electric fields in time. We study this
phenomenon in spatially inhomogeneous and bound electric fields by integrating
the equations of energymomentum and particle-number conservations and Maxwell
equations. The space and time evolutions of the pair-induced electric field,
electric charge- and currentdensities are calculated. The results show that
non-vanishing electric charge-density and the propagation of pair-induced
electric fields, differently from the case of homogeneous and unbound electric
fields. The space and time variations of pair-induced electric charges and
currents emit an electromagnetic radiation. We obtain the narrow spectrum and
intensity of this radiation, whose peak {\omega}peak locates in the region
around 4 KeV for electric field strength \sim Ec. We discuss their relevances
to both the laboratory experiments for electron and positron pair-productions
and the astrophysical observations of compact stars with an electromagnetic
structure.

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The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess