1,728 research outputs found
Black hole holography and mean field evolution
Holographic theories representing black holes are expected to exhibit quantum
chaos. We argue if the laws of quantum mechanics are expected to hold for
observers inside such black holes, then such holographic theories must have a
mean field approximation valid for typical black hole states, and for
timescales approaching the scrambling time. Using simple spin models as
examples, we examine the predictions of such an approach for observers inside
black holes, and more speculatively inside cosmological horizons.Comment: 11 pages, 5 figure
Quantum information erasure inside black holes
An effective field theory for infalling observers in the vicinity of a
quasi-static black hole is given in terms of a freely falling lattice
discretization. The lattice model successfully reproduces the thermal spectrum
of outgoing Hawking radiation, as was shown by Corley and Jacobson, but can
also be used to model observations made by a typical low-energy observer who
enters the black hole in free fall at a prescribed time. The explicit short
distance cutoff ensures that, from the viewpoint of the infalling observer, any
quantum information that entered the black hole more than a scrambling time
earlier has been erased by the black hole singularity. This property, combined
with the requirement that outside observers need at least of order the
scrambling time to extract quantum information from the black hole, ensures
that a typical infalling observer does not encounter drama upon crossing the
black hole horizon in a theory where black hole information is preserved for
asymptotic observers.Comment: 20 pages, 3 figures, some minor correction
Taking the Temperature of a Black Hole
We use the global embedding of a black hole spacetime into a higher
dimensional flat spacetime to define a local temperature for observers in free
fall outside a static black hole. The local free-fall temperature remains
finite at the event horizon and in asymptotically flat spacetime it approaches
the Hawking temperature at spatial infinity. Freely falling observers outside
an AdS black hole do not see any high-temperature thermal radiation even if the
Hawking temperature of such black holes can be arbitrarily high.Comment: latex, 14 pages, 4 figures, v3: added references, matches published
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D-Branes and Physical States
States obtained by projecting boundary states, associated with D-branes, to
fixed mass-level and momentum generically define non-trivial cohomology
classes. For on-shell states the cohomology is the standard one, but when the
states are off-shell the relevant cohomology is defined using a BRST operator
with ghost zero modes removed. The zero momentum cohomology falls naturally
into multiplets of . At the massless level, a simple set of D-brane
configurations generates the full set of zero-momentum states of standard ghost
number, including the discrete states. We give a general construction of
off-shell cohomology classes, which exhibits a non-trivial interaction between
left and right movers that is not seen in on-shell cohomology. This includes,
at higher mass levels, states obtained from typical D-brane boundary states as
well as states with more intricate ghost dependence.Comment: 22 pages, harvmac, no figure
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