Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hamiltonian self-adjoint extensions for (2+1)-dimensional Dirac
  particles   We study the stationary problem of a charged Dirac particle in (2+1)
dimensions in the presence of a uniform magnetic field B and a singular
magnetic tube of flux Phi = 2 pi kappa/e. The rotational invariance of this
configuration implies that the subspaces of definite angular momentum l+1/2 are
invariant under the action of the Hamiltonian H. We show that, for l different
from the integer part of kappa, the restriction of H to these subspaces,
  H_l is essentially self-adjoint, while for l equal to the integer part of
kappa, H_l admits a one-parameter family of self-adjoint extensions (SAE). In
the later case, the functions in the domain of H_l are singular (but
square-integrable) at the origin, their behavior being dictated by the value of
the parameter gamma that identifies the SAE. We also determine the spectrum of
the Hamiltonian as a function of kappa and gamma, as well as its closure.

26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph