709 research outputs found
A uniqueness theorem for degenerate Kerr-Newman black holes
We show that the domains of dependence of stationary, -regular,
analytic, electrovacuum space-times with a connected, non-empty, rotating,
degenerate event horizon arise from Kerr-Newman space-times
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A specialist toxicity database (TRACE) is more effective than its larger, commercially available counterparts
A comparison of the retrieval precision and recall of a specialist bibliographic toxicity database (TRACE) with that of a wide range of commercial on-line databases indicated that the larger size and resources of the commercial databases did not, for a series of test queries, assure superior retrieval of relevant papers. The specialist database, in which document selection and indexing is undertaken by the same (in this case) expert toxicologists who subsequently use the database in their day-to-day work, achieved markedly better retrieval, using simpler search strategies, than the commercial databases. Small specialist databases may offer a valuable alternative to existing commercial databases
On the uniqueness of smooth, stationary black holes in vacuum
We prove a conditional "no hair" theorem for smooth manifolds: if is the
domain of outer communication of a smooth, regular, stationary Einstein vacuum,
and if a technical condition relating the Ernst potential and Killing scalar is
satisfied on the bifurcate sphere, then is locally isometric to the domain
of outer communication of a Kerr space-time.Comment: Various correction
Uniqueness Theorem for Generalized Maxwell Electric and Magnetic Black Holes in Higher Dimensions
Based on the conformal energy theorem we prove the uniqueness theorem for
static higher dimensional electrically and magnetically charged black holes
being the solution of Einstein (n-2)-gauge forms equations of motion. Black
hole spacetime contains an asymptotically flat spacelike hypersurface with
compact interior and non-degenerate components of the event horizon.Comment: 7 pages, RevTex, to be published in Phys.Rev.D1
On the `Stationary Implies Axisymmetric' Theorem for Extremal Black Holes in Higher Dimensions
All known stationary black hole solutions in higher dimensions possess
additional rotational symmetries in addition to the stationary Killing field.
Also, for all known stationary solutions, the event horizon is a Killing
horizon, and the surface gravity is constant. In the case of non-degenerate
horizons (non-extremal black holes), a general theorem was previously
established [gr-qc/0605106] proving that these statements are in fact generally
true under the assumption that the spacetime is analytic, and that the metric
satisfies Einstein's equation. Here, we extend the analysis to the case of
degenerate (extremal) black holes. It is shown that the theorem still holds
true if the vector of angular velocities of the horizon satisfies a certain
"diophantine condition," which holds except for a set of measure zero.Comment: 30pp, Latex, no figure
A Higher Dimensional Stationary Rotating Black Hole Must be Axisymmetric
A key result in the proof of black hole uniqueness in 4-dimensions is that a
stationary black hole that is ``rotating''--i.e., is such that the stationary
Killing field is not everywhere normal to the horizon--must be axisymmetric.
The proof of this result in 4-dimensions relies on the fact that the orbits of
the stationary Killing field on the horizon have the property that they must
return to the same null geodesic generator of the horizon after a certain
period, . This latter property follows, in turn, from the fact that the
cross-sections of the horizon are two-dimensional spheres. However, in
spacetimes of dimension greater than 4, it is no longer true that the orbits of
the stationary Killing field on the horizon must return to the same null
geodesic generator. In this paper, we prove that, nevertheless, a higher
dimensional stationary black hole that is rotating must be axisymmetric. No
assumptions are made concerning the topology of the horizon cross-sections
other than that they are compact. However, we assume that the horizon is
non-degenerate and, as in the 4-dimensional proof, that the spacetime is
analytic.Comment: 24 pages, no figures, v2: footnotes and references added, v3:
numerous minor revision
Long-Time Behavior of Macroscopic Quantum Systems: Commentary Accompanying the English Translation of John von Neumann's 1929 Article on the Quantum Ergodic Theorem
The renewed interest in the foundations of quantum statistical mechanics in
recent years has led us to study John von Neumann's 1929 article on the quantum
ergodic theorem. We have found this almost forgotten article, which until now
has been available only in German, to be a treasure chest, and to be much
misunderstood. In it, von Neumann studied the long-time behavior of macroscopic
quantum systems. While one of the two theorems announced in his title, the one
he calls the "quantum H-theorem", is actually a much weaker statement than
Boltzmann's classical H-theorem, the other theorem, which he calls the "quantum
ergodic theorem", is a beautiful and very non-trivial result. It expresses a
fact we call "normal typicality" and can be summarized as follows: For a
"typical" finite family of commuting macroscopic observables, every initial
wave function from a micro-canonical energy shell so evolves that for
most times in the long run, the joint probability distribution of these
observables obtained from is close to their micro-canonical
distribution.Comment: 34 pages LaTeX, no figures; v2: minor improvements and additions. The
English translation of von Neumann's article is available as arXiv:1003.213
Uniqueness of (dilatonic) charged black holes and black p-branes in higher dimensions
We prove the uniqueness of higher dimensional (dilatonic) charged black holes
in static and asymptotically flat spacetimes for arbitrary vector-dilaton
coupling constant. An application to the uniqueness of a wide class of black
p-branes is also given.Comment: 6 page
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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