Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An exact evaluation of the Casimir energy in two planar models   The method of images is used to calculate the Casimir energy in Euclidean
space with Dirichlet boundary conditions for two planar models, namely: i. the
non-relativistic Landau problem for a charged particle of mass m for which -
irrespective of the sign of the charge - the energy is negative, and ii. the
model of a real, massive, noninteracting relativistic scalar field theory in 2
+ 1 dimensions, for which the Casimir energy density is non-negative and is
expressed in terms of the Lerch transcendent xxx and the polylogarithm xxx with
0 < xxx < 1 and n = 2, 3.

6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an