Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mode-sum regularization of $\left\langle \phi^{2} \right\rangle$ in the
  angular-splitting method   The computation of the renormalized stress-energy tensor or
$\left\langle\phi^{2}\right\rangle_{ren}$ in curved spacetime is a challenging
task, at both the conceptual and technical levels. Recently we developed a new
approach to compute such renormalized quantities in asymptotically-flat curved
spacetimes, based on the point-splitting procedure. Our approach requires the
spacetime to admit some symmetry. We already implemented this approach to
compute $\left\langle \phi^{2}\right\rangle _{ren}$ in a stationary spacetime
using t-splitting, namely splitting in the time-translation direction. Here we
present the angular-splitting version of this approach, aimed for computing
renormalized quantities in a general (possibly dynamical) spherically-symmetric
spacetime. To illustrate how the angular-splitting method works, we use it here
to compute $\left\langle \phi^{2}\right\rangle _{ren}$ for a quantum massless
scalar field in Schwarzschild background, in various quantum states (Boulware,
Unruh, and Hartle-Hawking states). We find excellent agreement with the results
obtained from the t-splitting variant, and also with other methods. Our main
goal in pursuing this new mode-sum approach was to enable the computation of
the renormalized stress-energy tensor in a dynamical spherically symmetric
background, e.g. an evaporating black hole. The angular-splitting variant
presented here is most suitable to this purpose.

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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: quant-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: physics
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
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The categories of this paper are: eess
0
The categories of this paper are: hep-ph