8,470 research outputs found
Painlev\'{e}-Gullstrand-type coordinates for the five-dimensional Myers-Perry black hole
The Painleve-Gullstrand coordinates provide a convenient framework for
presenting the Schwarzschild geometry because of their flat constant-time
hypersurfaces, and the fact that they are free of coordinate singularities
outside r=0. Generalizations of Painleve-Gullstrand coordinates suitable for
the Kerr geometry have been presented by Doran and Natario. These coordinate
systems feature a time coordinate identical to the proper time of
zero-angular-momentum observers that are dropped from infinity. Here, the
methods of Doran and Natario are extended to the five-dimensional rotating
black hole found by Myers and Perry. The result is a new formulation of the
Myers-Perry metric. The properties and physical significance of these new
coordinates are discussed.Comment: 15 page
Coordinate families for the Schwarzschild geometry based on radial timelike geodesics
We explore the connections between various coordinate systems associated with
observers moving inwardly along radial geodesics in the Schwarzschild geometry.
Painlev\'e-Gullstrand (PG) time is adapted to freely falling observers dropped
from rest from infinity; Lake-Martel-Poisson (LMP) time coordinates are adapted
to observers who start at infinity with non-zero initial inward velocity;
Gautreau-Hoffmann (GH) time coordinates are adapted to observers dropped from
rest from a finite distance from the black hole horizon. We construct from
these an LMP family and a proper-time family of time coordinates, the
intersection of which is PG time. We demonstrate that these coordinate families
are distinct, but related, one-parameter generalizations of PG time, and show
linkage to Lema\^itre coordinates as well.Comment: 13 pages and 10 figures. New title and abstract; expanded discussion
on Gautreau-Hoffmann coordinates, and coordinate classifications; figures
added; references added. Submitted for publicatio
Solutions of the Yang-Baxter equation: descendants of the six-vertex model from the Drinfeld doubles of dihedral group algebras
The representation theory of the Drinfeld doubles of dihedral groups is used
to solve the Yang-Baxter equation. Use of the 2-dimensional representations
recovers the six-vertex model solution. Solutions in arbitrary dimensions,
which are viewed as descendants of the six-vertex model case, are then obtained
using tensor product graph methods which were originally formulated for quantum
algebras. Connections with the Fateev-Zamolodchikov model are discussed.Comment: 34 pages, 2 figure
Computing the Mertens and Meissel-Mertens constants for sums over arithmetic progressions
We give explicit numerical values with 100 decimal digits for the Mertens
constant involved in the asymptotic formula for and, as a by-product, for the Meissel-Mertens constant
defined as , for , ...,
and .Comment: 12 pages, 6 table
Integrable boundary conditions for a non-abelian anyon chain with symmetry
A general formulation of the Boundary Quantum Inverse Scattering Method is
given which is applicable in cases where -matrix solutions of the
Yang--Baxter equation do not have the property of crossing unitarity. Suitably
modified forms of the reflection equations are presented which permit the
construction of a family of commuting transfer matrices. As an example, we
apply the formalism to determine the most general solutions of the reflection
equations for a solution of the Yang-Baxter equation with underlying symmetry
given by the Drinfeld double of the dihedral group . This
-matrix does not have the crossing unitarity property. In this manner we
derive integrable boundary conditions for an open chain model of interacting
non-abelian anyons
Reference Standards for Body Fat Measure Using GE Dual Energy X-Ray Absorptiometry in Caucasian Adults
Background Dual energy x-ray absorptiometry (DXA) is an established technique for the measurement of body composition. Reference values for these variables, particularly those related to fat mass, are necessary for interpretation and accurate classification of those at risk for obesityrelated health complications and in need of lifestyle modifications (diet, physical activity, etc.). Currently, there are no reference values available for GE-Healthcare DXA systems and it is known that whole-body and regional fat mass measures differ by DXA manufacturer.
Objective To develop reference values by age and sex for DXA-derived fat mass measurements with GE-Healthcare systems.
Methods A de-identified sample of 3,327 participants (2,076 women, 1,251 men) was obtained from Ball State University\u27s Clinical Exercise Physiology Laboratory and University of Wisconsin- Milwaukee\u27s Physical Activity & Health Research Laboratory. All scans were completed using a GE Lunar Prodigy or iDXA and data reported included percent body fat (%BF), fat mass index (FMI), and ratios of android-to-gynoid (A/G), trunk/limb, and trunk/leg fat measurements. Percentiles were calculated and a factorial ANOVA was used to determine differences in the mean values for each variable between age and sex.
Results Normative reference values for fat mass variables from DXA measurements obtained from GE-Healthcare DXA systems are presented as percentiles for both women and men in 10- year age groups. Women had higher (p\u3c0.01) mean %BF and FMI than men, whereas men had higher (p\u3c0.01) mean ratios of A/G, trunk/limb, and trunk/leg fat measurements than women
Universal Baxterization for -graded Hopf algebras
We present a method for Baxterizing solutions of the constant Yang-Baxter
equation associated with -graded Hopf algebras. To demonstrate the
approach, we provide examples for the Taft algebras and the quantum group
.Comment: 8 page
Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam
The T2K experiment observes indications of nu(mu) -> nu(mu) e appearance in data accumulated with 1.43 x 10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Delta m(23)(2)| = 2.4 x 10(-3) eV(2), sin(2)2 theta(23) = 1 and sin(2)2 theta(13) = 0, the expected number of such events is 1.5 +/- 0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7 x 10(-3), equivalent to 2.5 sigma significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2 theta(13) < 0.28(0.34) for delta(CP) = 0 and a normal (inverted) hierarchy
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