Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exotic atoms in two dimensions   We study the behavior of energy levels in two dimensions for exotic atoms,
i.e., when a long-range attractive potential is supplemented by a short-range
interaction, and compare the results with these of the one- and
three-dimensional cases. The energy shifts are well reproduced by a scattering
length formula $ \delta{E}= A_0^2/\ln (a/R)$, where $a$ is the scattering
length in the short-range potential, $A_0^2/(2\,\pi)$ the square of the wave
function at the origin in the external potential, and $R$ is related to the
derivative with respect to the energy of the solution that is regular at large
distances.

1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg