2,491 research outputs found
Black hole information, unitarity, and nonlocality
The black hole information paradox apparently indicates the need for a
fundamentally new ingredient in physics. The leading contender is nonlocality.
Possible mechanisms for the nonlocality needed to restore unitarity to black
hole evolution are investigated. Suggestions that such dynamics arises from
ultra-planckian modes in Hawking's derivation are investigated and found not to
be relevant, in a picture using smooth slices spanning the exterior and
interior of the horizon. However, no simultaneous description of modes that
have fallen into the black hole and outgoing Hawking modes can be given without
appearance of a large kinematic invariant, or other dependence on
ultra-planckian physics; a reliable argument for information loss thus has not
been constructed. This suggests that strong gravitational dynamics is
important. Such dynamics has been argued to be fundamentally nonlocal in
extreme situations, such as those required to investigate the fate of
information.Comment: 34 pages, 4 figures. Major revision of hep-th/0604047. v2: minor
corrections and added referenc
Digitizing zone maps, using modified LARSYS program
A method for digitizing zone maps is presented, starting with colored images and producing a final one-channel digitized tape. This method automates the work previously done interactively on the Image-100 and Data Analysis System computers of the Johnson Space Center (JSC) Earth Observations Division (EOD). A color-coded map was digitized through color filters on a scanner to form a digital tape in LARSYS-2 or JSC Universal format. The taped image was classified by the EOD LARSYS program on the basis of training fields included in the image. Numerical values were assigned to all pixels in a given class, and the resulting coded zone map was written on a LARSYS or Universal tape. A unique spatial filter option permitted zones to be made homogeneous and edges of zones to be abrupt transitions from one zone to the next. A zoom option allowed the output image to have arbitrary dimensions in terms of number of lines and number of samples on a line. Printouts of the computer program are given and the images that were digitized are shown
Locality in quantum gravity and string theory
Breakdown of local physics in string theory at distances longer than the
string scale is investigated. Such nonlocality would be expected to be visible
in ultrahigh-energy scattering. The results of various approaches to such
scattering are collected and examined. No evidence is found for non-locality
from strings whose length grows linearly with the energy. However, local
quantum field theory does apparently fail at scales determined by gravitational
physics, particularly strong gravitational dynamics. This amplifies locality
bound arguments that such failure of locality is a fundamental aspect of
physics. This kind of nonlocality could be a central element of a possible
loophole in the argument for information loss in black holes.Comment: 26 pages, 3 figures, harvmac. v2: minor changes to bring into accord
with revised paper hep-th/060519
High energy QCD scattering, the shape of gravity on an IR brane, and the Froissart bound
High-energy scattering in non-conformal gauge theories is investigated using
the AdS/CFT dual string/gravity theory. It is argued that strong-gravity
processes, such as black hole formation, play an important role in the dual
dynamics. Further information about this dynamics is found by performing a
linearized analysis of gravity for a mass near an infrared brane; this gives
the far field approximation to black hole or other strong-gravity effects, and
in particular allows us to estimate their shape. From this shape, one can infer
a total scattering cross-section that grows with center of mass energy as ln^2
E, saturating the Froissart bound.Comment: 27 pages, 1 fig, harvmac. v2: references added, typos corrected v3:
typo correcte
Nonlocality vs. complementarity: a conservative approach to the information problem
A proposal for resolution of the information paradox is that "nice slice"
states, which have been viewed as providing a sharp argument for information
loss, do not in fact do so as they do not give a fully accurate description of
the quantum state of a black hole. This however leaves an information
*problem*, which is to provide a consistent description of how information
escapes when a black hole evaporates. While a rather extreme form of
nonlocality has been advocated in the form of complementarity, this paper
argues that is not necessary, and more modest nonlocality could solve the
information problem. One possible distinguishing characteristic of scenarios is
the information retention time. The question of whether such nonlocality
implies acausality, and particularly inconsistency, is briefly addressed. The
need for such nonlocality, and its apparent tension with our empirical
observations of local quantum field theory, may be a critical missing piece in
understanding the principles of quantum gravity.Comment: 11 pages of text and figures, + references. v2 minor text. v3 small
revisions to match final journal versio
Precursors, black holes, and a locality bound
We revisit the problem of precursors in the AdS/CFT correspondence.
Identification of the precursors is expected to improve our understanding of
the tension between holography and bulk locality and of the resolution of the
black hole information paradox. Previous arguments that the precursors are
large, undecorated Wilson loops are found to be flawed. We argue that the role
of precursors should become evident when one saturates a certain locality
bound. The spacetime uncertainty principle is a direct consequence of this
bound.Comment: 26 pages, 8 figs; reference added, minor clarification in sec. 2;
incorrect draft mistakenly used in version
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