Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Black Holes or Firewalls: A Theory of Horizons   We present a quantum theory of black hole (and other) horizons, in which the
standard assumptions of complementarity are preserved without contradicting
information theoretic considerations. After the scrambling time, the quantum
mechanical structure of a black hole becomes that of an eternal black hole at
the microscopic level. In particular, the stretched horizon degrees of freedom
and the states entangled with them can be mapped into the near-horizon modes in
the two exterior regions of an eternal black hole, whose mass is taken to be
that of the evolving black hole at each moment. Salient features arising from
this picture include: (i) the number of degrees of freedom needed to describe a
black hole is e^{A/2 l_P^2}, where A is the area of the horizon; (ii) black
hole states having smooth horizons span only an e^{A/4 l_P^2}-dimensional
subspace of the relevant e^{A/2 l_P^2}-dimensional Hilbert space; (iii)
internal dynamics of the horizon is such that an infalling observer finds a
smooth horizon with probability 1 if a state stays in this subspace. We
identify the structure of local operators in the exterior and interior
spacetime regions, and show that this structure avoids firewall arguments---the
horizon can keep being smooth throughout the evolution. We discuss the fate of
falling observers under various circumstances, especially when they manipulate
degrees of freedom before entering the horizon, and find that an observer can
never see a firewall by making a measurement on early Hawking radiation. We
also consider the framework in an infalling reference frame, and argue that
Minkowski-like vacua are not unique. In particular, the number of true
Minkowski vacua is infinite, although the label discriminating these vacua
cannot be accessed in usual non-gravitational quantum field theory. An
application to de Sitter horizons is also discussed.

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The categories of this paper are: patt-sol
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The categories of this paper are: stat
2
The categories of this paper are: math
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-ex
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The categories of this paper are: acc-phys