Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wightman function and the Casimir effect for a Robin sphere in a
  constant curvature space   We evaluate the Wightman function, the mean field squared and the vacuum
expectation value (VEV) of the energy-momentum tensor for a scalar field with
Robin boundary condition on a spherical shell in the background of a constant
negative curvature space. For the coefficient in the boundary condition there
is a critical value above which the scalar vacuum becomes unstable. In both
interior and exterior regions, the VEVs are decomposed into the boundary-free
and sphere-induced contributions. For the latter, rapidly convergent integral
representations are provided. In the region inside the sphere, the eigenvalues
are expressed in terms of the zeros of the combination of the associated
Legendre function and its derivative and the decomposition is achieved by
making use of the Abel-Plana type summation formula for the series over these
zeros. The sphere-induced contribution to the VEV of the field squared is
negative for Dirichlet boundary condition and positive for Neumann one. At
distances from the sphere larger than the curvature scale of the background
space the suppression of the vacuum fluctuations in the gravitational field
corresponding to the negative curvature space is stronger compared with the
case of the Minkowskian bulk. In particular, the decay of the VEVs with the
distance is exponential for both massive and massless fields. The corresponding
results are generalized for spaces with spherical bubbles and for cosmological
models with negative curvature spaces.

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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: nucl-th
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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: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: acc-phys