Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effective one-body approach to the relativistic two-body problem   The relativistic 2-body problem, much like the non-relativistic one, is
reduced to describing the motion of an effective particle in an external field.
The concept of a relativistic reduced mass and effective particle energy
introduced some 30 years ago to compute relativistic corrections to the Balmer
formula in quantum electrodynamics, is shown to work equally well for classical
electromagnetic and gravitational interaction. The results for the
gravitational 2-body problem have more than academic interest since they apply
to the study of binary pulsars that provide precision tests for general
relativity. They are compared with recent results derived by other methods.

9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn