Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum Amplitudes in Black-Hole Evaporation: Complex Approach and
  Spin-0 Amplitude   We consider the quantum-mechanical decay of a Schwarzschild-like black hole
formed by gravitational collapse into almost-flat space-time and weak radiation
at a late time. We evaluate quantum amplitudes (not just probabilities) for
transitions from initial to final states, and show that no information is lost
in collapse to a black hole. Boundary data for the gravitational field and a
scalar field are posed on an initial space-like hypersurface $\Sigma_I$ and a
final surface $\Sigma_F$. These asymptotically-flat 3-surfaces are separated by
a Lorentzian proper-time interval $T$, measured at spatial infinity. The
boundary-value problem is made well-posed, classically and
quantum-mechanically, by rotating $T$ into the lower-half complex plane: $T\to
{\mid}T{\mid}\exp(-i\theta), 0<\theta\leq\pi/2$. This corresponds to Feynman's
$+i\epsilon$ prescription. For the classical boundary-value problem, we
calculate the second-variation classical Lorentzian action $S^{(2)}_{class}$ as
a functional of the boundary data. Following Feynman, the Lorentzian quantum
amplitude is recovered in the limit $\theta\to 0_{+}$ from the well-defined
complex-$T$ amplitude. Dirac's canonical approach to the quantisation of
constrained systems shows that for locally-supersymmetric theories of gravity
the amplitude is exactly semi-classical: $\exp(i S^{(2)}_{class})$ for weak
perturbations, apart from delta-functionals of the supersymmetry constraints.
We treat such quantum amplitudes for weak scalar-field configurations on
$\Sigma_F$, taking the weak final gravitational field to be spherically
symmetric. The treatment involves adiabatic solutions of the scalar wave
equation. This extends our previous work, giving explicit expressions for the
real and imaginary parts of such quantum amplitudes.

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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat