Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonorientable spacetime tunneling   Misner space is generalized to have the nonorientable topology of a Klein
bottle, and it is shown that in a classical spacetime with multiply connected
space slices having such a topology, closed timelike curves are formed.
Different regions on the Klein bottle surface can be distinguished which are
separated by apparent horizons fixed at particular values of the two angular
variables that eneter the metric. Around the throat of this tunnel (which we
denote a Klein bottlehole), the position of these horizons dictates an ordinary
and exotic matter distribution such that, in addition to the known diverging
lensing action of wormholes, a converging lensing action is also present at the
mouths. Associated with this matter distribution, the accelerating version of
this Klein bottlehole shows four distinct chronology horizons, each with its
own nonchronal region. A calculation of the quantum vacuum fluctuations
performed by using the regularized two-point Hadamard function shows that each
chronology horizon nests a set of polarized hypersurfaces where the
renormalized momentum-energy tensor diverges. This quantum instability can be
prevented if we take the accelerating Klein bottlehole to be a generalization
of a modified Misner space in which the period of the closed spatial direction
is time-dependent. In this case, the nonchronal regions and closed timelike
curves cannot exceed a minimum size of the order the Planck scale.

11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int