Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ray-tracing and Interferometry in Schwarzschild Geometry   Here, we investigate the possible optical anisotropy of vacuum due to
gravitational field. In doing this, we provide sufficient evidence from direct
coordinate integration of the null-geodesic equations obtained from the
Lagrangian method, as well as ray-tracing equations obtained from the
Plebanski's equivalent medium theory. All calculations are done for the
Schwarzschild geometry, which results in an anisotropic (pseudo-isotropic)
optical equivalent medium when Cartesian coordinates are taken. We confirm that
the results of ray-tracing in the equivalent medium and null geodesics are
exactly the same, while they are in disagreement with the results of
integration in the conventional isotropic equivalent medium of Schwarzschild
geometry. Based on the principle invariance of physical due to coordinate
transformation, there exist just one result. This Contradiction will be solved
by tensor algebra and it will be shown that the conventional isotropic approach
is wrong, and even by making isotropic of the metric, the optical behavior of
vacuum will remain anisotropic. Hence, we conclude that the true optical
behavior of curved spacetime must be anisotropic, and it is an intrinsic
property of vacuum in the presence of gravitational field. We provide further
discussions on how to detect this possible anisotropy, and what further
consequences might be expected in the interpretation of gravtiational lensing
data.

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The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
30
The categories of this paper are: q-alg