Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Time and space dependence of electromagnetic field in relativistic
  heavy-ion collisions   Exact analytical solution for the space-time evolution of electromagnetic
field in electrically conducting nuclear matter produced in heavy-ion
collisions is discussed. It is argued that the parameter that controls the
strength of the matter effect on the field evolution is $\sigma\gamma b$, where
$\sigma$ is electrical conductivity, $\gamma$ is the Lorentz boost-factor and
$b$ is the characteristic transverse size of the matter. When this parameter is
of the order one or larger, which is the case at RHIC and LHC, space-time
dependence of electromagnetic field is completely different form that in
vacuum.

36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio