Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Accelerated observers and the notion of singular spacetime   Geodesic completeness is typically regarded as a basic criterion to determine
whether a given spacetime is regular or singular. However, the principle of
general covariance does not privilege any family of observers over the others
and, therefore, observers with arbitrary motions should be able to provide a
complete physical description of the world. This suggests that in a regular
spacetime, all physically acceptable observers should have complete paths. In
this work we explore this idea by studying the motion of accelerated observers
in spherically symmetric spacetimes and illustrate it by considering two
geodesically complete black hole spacetimes recently described in the
literature. We show that for bound and locally unbound accelerations, the paths
of accelerated test particles are complete, providing further support to the
regularity of such spacetimes.

12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an