Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: String-Like Electrostatic Interaction from QED with Infinite Magnetic
  Field   In the limit of infinite external magnetic field B the static field of an
electric charge is squeezed into a string parallel to B. Near the charge the
potential grows like |x_3|(ln |x_3| + const) with the coordinate x_3 along the
string. The energy of the string breaking is finite and very close to the
effective photon mass.

23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph