10,414 research outputs found
Firewalls in AdS/CFT
Several recent papers argue against firewalls by relaxing the requirement for
locality outside the stretched horizon. In the firewall argument, locality
essentially serves the purpose of ensuring that the degrees of freedom required
for infall are those in the proximity of the black hole and not the ones in the
early radiation. We make the firewall argument sharper by utilizing the AdS/CFT
framework and claim that the firewall argument essentially states that the dual
to a thermal state in the CFT is a firewall.Comment: 11 pages plus references, 8 figures; version accepted for publication
in JHE
Unitarity and fuzzball complementarity: "Alice fuzzes but may not even know it!"
We investigate the recent black hole firewall argument. For a black hole in a
typical state we argue that unitarity requires every quantum of radiation
leaving the black hole to carry information about the initial state. An
information-free horizon is thus inconsistent with unitary at every step of the
evaporation process (in particular both before and after Page time). The
required horizon-scale structure is manifest in the fuzzball proposal which
provides a mechanism for holding up the structure. In this context we want to
address the experience of an infalling observer and discuss the recent fuzzball
complementarity proposal. Unlike black hole complementarity and observer
complementarity which postulate asymptotic observers experience a hot membrane
while infalling ones pass freely through the horizon, fuzzball complementarity
postulates that fine-grained operators experience the details of the fuzzball
microstate and coarse-grained operators experience the black hole. In
particular, this implies that an infalling detector tuned to energy E ~ T,
where T is the asymptotic Hawking temperature, does not experience free infall
while one tuned to E >> T does.Comment: v3: 33 pages + citations, 8 figures, version accepted for publicatio
Operating experiences of retardant bombers during firefighting operations
Data are presented on operational practices and maneuver accelerations experienced by two Douglas DC-6B airplanes converted to retardant bombers and used in firefighting operations. The data cover two fire seasons in the mountainous regions of the northwestern United States
Virtual Data in CMS Analysis
The use of virtual data for enhancing the collaboration between large groups
of scientists is explored in several ways:
- by defining ``virtual'' parameter spaces which can be searched and shared
in an organized way by a collaboration of scientists in the course of their
analysis;
- by providing a mechanism to log the provenance of results and the ability
to trace them back to the various stages in the analysis of real or simulated
data;
- by creating ``check points'' in the course of an analysis to permit
collaborators to explore their own analysis branches by refining selections,
improving the signal to background ratio, varying the estimation of parameters,
etc.;
- by facilitating the audit of an analysis and the reproduction of its
results by a different group, or in a peer review context.
We describe a prototype for the analysis of data from the CMS experiment
based on the virtual data system Chimera and the object-oriented data analysis
framework ROOT. The Chimera system is used to chain together several steps in
the analysis process including the Monte Carlo generation of data, the
simulation of detector response, the reconstruction of physics objects and
their subsequent analysis, histogramming and visualization using the ROOT
framework.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 9 pages, LaTeX, 7 eps figures. PSN
TUAT010. V2 - references adde
Impact of multiscale dynamical processes and mixing on the chemical composition of the upper troposphere and lower stratosphere during the Intercontinental Chemical Transport Experiment–North America
We use high-frequency in situ observations made from the DC8 to examine fine-scale tracer structure and correlations observed in the upper troposphere and lower stratosphere during INTEX-NA. Two flights of the NASA DC-8 are compared and contrasted. Chemical data from the DC-8 flight on 18 July show evidence for interleaving and mixing of polluted and stratospheric air masses in the vicinity of the subtropical jet in the upper troposphere, while on 2 August the DC-8 flew through a polluted upper troposphere and a lowermost stratosphere that showed evidence of an intrusion of polluted air. We compare data from both flights with RAQMS 3-D global meteorological and chemical model fields to establish dynamical context and to diagnose processes regulating the degree of mixing on each day. We also use trajectory mapping of the model fields to show that filamentary structure due to upstream strain deformation contributes to tracer variability observed in the upper troposphere. An Eulerian measure of strain versus rotation in the large-scale flow is found useful in predicting filamentary structure in the vicinity of the jet. Higher-frequency (6–24 km) tracer variability is attributed to buoyancy wave oscillations in the vicinity of the jet, whose turbulent dissipation leads to efficient mixing across tracer gradients
Compressive Properties of Enamel, Dental Cements, and Gold
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68038/2/10.1177_00220345610400051901.pd
- …