Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Schwarzschild black hole as accelerator of accelerated particles   We consider collision of two particles near the horizon of a nonextremal
static black hole. At least one of them is accelerated. We show that the energy
$E_{c.m.}$ in the center of mass can become unbounded in spite of the fact that
a black hole is neither rotating nor electrically charged. In particular, this
happens even for the Schwarzschild black hole. The key ingredient that makes it
possible is the presence of positive acceleration (repulsion). Then, if one of
particles is fine-tuned properly, the effect takes place. This acceleration can
be caused by an external force in the case of particles or some engine in the
case of a macroscopic body ("rocket"). If the force is attractive, $E_{c.m.}$
is bounded but, instead, the analogue of the Penrose effect is possible.

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The categories of this paper are: stat
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
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The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys