18,453 research outputs found
Global Scaling Symmetry, Noether Charge and Universality of Shear Viscosity
Recently it was established in Einstein-Maxwell-Dilaton gravity that the KSS
viscosity/entropy ratio associated with AdS planar black holes can be viewed as
the boundary dual to the generalized Smarr relation of the black holes in the
bulk. In this paper we establish this relation in Einstein gravity with general
minimally-coupled matter, and also in theories with an additional non-minimally
coupled scalar field. We consider two examples for explicit demonstrations.Comment: 16 pages, no figur
How to understand the underlying structures of , , and
We investigate the possible rescattering effects which may contribute to the
process . It is shown that the
rescattering via the open-charmed meson loops, and
rescattering via the loops may simulate the structures of
and , respectively. However, if the quantum numbers of
() are (), it is hard to to ascribe the
observation of and to the -wave threshold rescattering
effects, which implies that and could be genuine
resonances. We also suggest that may be the conventional orbitally
excited state .Comment: 14 pages, 5 figures, 1 tabl
A semiparametric regression model for paired longitudinal outcomes with application in childhood blood pressure development
This research examines the simultaneous influences of height and weight on
longitudinally measured systolic and diastolic blood pressure in children.
Previous studies have shown that both height and weight are positively
associated with blood pressure. In children, however, the concurrent increases
of height and weight have made it all but impossible to discern the effect of
height from that of weight. To better understand these influences, we propose
to examine the joint effect of height and weight on blood pressure. Bivariate
thin plate spline surfaces are used to accommodate the potentially nonlinear
effects as well as the interaction between height and weight. Moreover, we
consider a joint model for paired blood pressure measures, that is, systolic
and diastolic blood pressure, to account for the underlying correlation between
the two measures within the same individual. The bivariate spline surfaces are
allowed to vary across different groups of interest. We have developed related
model fitting and inference procedures. The proposed method is used to analyze
data from a real clinical investigation.Comment: Published in at http://dx.doi.org/10.1214/12-AOAS567 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Lifshitz and Schrodinger Vacua, Superstar Resolution in Gauged Maximal Supergravities
We consider the subset of gauged maximal supergravities that consists of the
SO(n+1) gauge fields A^{ij} and the scalar deformation T^{ij} of the S^n in the
spherical reduction of M-theory or type IIB. We focus on the Abelian Cartan
subgroup and the diagonal entries of T^{ij}. The resulting theories can be
viewed as the STU models with additional hyperscalars. We find that the
theories with only one or two such vectors can be generalized naturally to
arbitrary dimensions. The same is true for the D=4 or 5 Einstein-Maxwell theory
with such a hyperscalar. The gauge fields become massive, determined by
stationary points of the hyperscalars a la the analogous Abelian Higgs
mechanism. We obtain classes of Lifshitz and Schrodinger vacua in these
theories. The scaling exponent z turns out to be rather restricted, taking
fractional or irrational numbers. Tweaking the theories by relaxing the mass
parameter or making a small change of the superpotential, we find that
solutions with z=2 can emerge. In a different application, we find that the
resolution of superstar singularity in the STU models by using bubbling-AdS
solitons can be generalized to arbitrary dimensions in our theories. In
particular, we obtain the smooth AdS solitons that can be viewed as the
resolution of the Reissner-Nordstrom superstars in general dimensions.Comment: Latex, 24 page
Thermodynamics of Lifshitz Black Holes
We specialize the Wald formalism to derive the thermodynamical first law for
static black holes with spherical/torus/hyperbolic symmetries in a variety of
supergravities or supergravity-inspired theories involving multiple scalars and
vectors. We apply the formula to study the first law of a general class of
Lifshitz black holes. We analyse the first law of three exact Lifshitz black
holes and the results fit the general pattern. In one example, the first law is
where are the electric potential and charge of the
Maxwell field. The unusual vanishing of mass in this specific solution
demonstrates that super-extremal charged black holes can exist in asymptotic
Lifshitz spacetimes.Comment: 27 page
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