Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct numerical solution of the two-particle Lippmann-Schwinger
  equation in coordinate space using the multi-variable Nystrom method   Direct numerical solution of the coordinate-space integral-equation version
of the two-particle Lippmann Schwinger (LS) equation is considered as a means
of avoiding the shortcomings of partial-wave expansion at high energies and in
the context of few-body problems. Upon the regularization of the singular
kernel of the three-dimensional LS equation by a subtraction technique, a
three-variate quadrature rule is used to solve the resulting nonsingular
integral equation. To avoid the computational burden of discretizing three
variables, advantage is taken of the fact that, for central potentials,
azimuthal angle can be integrated out leaving a two-variable reduced integral
equation. Although the singularity in the the kernel of the two-variable
integral equation is weaker than that of the three-dimensional equation, it
nevertheless requires careful handling for quadrature discretization to be
applicable. A regularization method for the kernel of the two-variable integral
equation is derived from the treatment of the singularity in the
three-dimensional equation. A quadrature rule constructed as the direct-product
of single-variable quadrature rules for radial distance and polar angle is used
to discretize the two-variable integral equation. These two- and three-variable
methods are tested on a model nucleon-nucleon potential. The results show that
Nystrom method for the coordinate-space LS equation compares favorably in terms
of its ease of implementation and effectiveness with the Nystrom method for the
momentum-space version of the LS equation .

15
The categories of this paper are: nucl-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
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The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: stat