Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Boundary Integral Method for Stationary States of Two-Dimensional
  Quantum Systems   The boundary integral method for calculating the stationary states of a
quantum particle in nano-devices and quantum billiards is presented in detail
at an elementary level. According to the method, wave functions inside the
domain of the device or billiard are expressed in terms of line integrals of
the wave function and its normal derivative along the domain's boundary; the
respective energy eigenvalues are obtained as the roots of Fredholm
determinants. Numerical implementations of the method are described and applied
to determine the energy level statistics of billiards with circular and stadium
shapes and demonstrate the quantum mechanical characteristics of chaotic
motion. The treatment of other examples as well as the advantages and
limitations of the boundary integral method are discussed.

11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
18
The categories of this paper are: econ