Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing crunching AdS cosmologies   Holographic gravity duals of deformations of CFTs formulated on de Sitter
spacetime contain FRW geometries behind a horizon, with cosmological big crunch
singularities. Using a specific analytically tractable solution within a
particular single scalar truncation of N=8 supergravity on AdS_4, we first
probe such crunching cosmologies with spacelike radial geodesics that compute
spatially antipodal correlators of large dimension boundary operators. At late
times, the geodesics lie on the FRW slice of maximal expansion behind the
horizon. The late time two-point functions factorise, and when transformed to
the Einstein static universe, they exhibit a temporal non-analyticity
determined by the maximal value of the scale factor a_{max} . Radial geodesics
connecting antipodal points necessarily have de Sitter energy E \leq a_{max},
while geodesics with E > a_{max} terminate at the crunch, the two categories of
geodesics being separated by the maximal expansion slice. The spacelike crunch
singularity is curved "outward" in the Penrose diagram for the deformed AdS
backgrounds, and thus geodesic limits of the antipodal correlators do not
directly probe the crunch. Beyond the geodesic limit, we point out that the
scalar wave equation, analytically continued into the FRW patch, has a
potential which is singular at the crunch along with complex WKB turning points
in the vicinity of the FRW crunch. We then argue that the frequency space
Green's function has a branch point determined by a_{max} which corresponds to
the lowest quasinormal frequency.

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The categories of this paper are: cs
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The categories of this paper are: funct-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: mtrl-th
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The categories of this paper are: math
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The categories of this paper are: nlin
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int