Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modified Coulomb potential with virtual photons following a canonical
  distribution   The need for a cutoff in the Lamb shift calculation suggests that high-energy
virtual photons do not interact with real particles. In this paper, we assume
that the creation of virtual photons follows a canonical distribution. As a
result, the Coulomb potential is modified to $V(r)=- ze^2\arctan (m_c
r)/(2\pi^2 r)$, and the zero-point energy density of the electromagnetic field
becomes finite.

15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn