Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two charges on plane in a magnetic field: II. Moving neutral quantum
  system across a magnetic field   The moving neutral system of two Coulomb charges on a plane subject to a
constant magnetic field $B$ perpendicular to the plane is considered. It is
shown that the composite system of finite total mass is bound for any
center-of-mass momentum $P$ and magnetic field strength; the energy of the
ground state is calculated accurately using a variational approach. Their
accuracy is cross-checked in a Lagrange-mesh method for $B=1$ a.u. and in a
perturbation theory at small $B$ and $P$. The constructed trial function has
the property of being a uniform approximation of the exact eigenfunction. For a
Hydrogen atom and a Positronium a double perturbation theory in $B$ and $P$ is
developed and the first corrections are found algebraically. A phenomenon of a
sharp change of energy behavior for a certain center-of-mass momentum and a
fixed magnetic field is indicated.

30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con