146,559 research outputs found
Surplus Angle and Sign-flipped Coulomb Force in Projectable Horava-Lifshitz Gravity
We obtain the static spherically symmetric vacuum solutions of
Horava-Lifshitz gravity theory, imposing the detailed balance condition only in
the UV limit. We find the solutions in two different coordinate systems, the
Painlev\'e-Gullstrand coordinates and the Poincare coordinates, to examine the
consequences of imposing the projectability condition. The solutions in two
coordinate systems are distinct due to the non-relativistic nature of the HL
gravity. In the Painleve-Gullstrand coordinates complying with the
projectability condition, the solution involves an additional integration
constant which yields surplus angle and implies attractive Coulomb force
between same charges.Comment: 13 page
New identities involving q-Euler polynomials of higher order
In this paper we give new identities involving q-Euler polynomials of higher
order.Comment: 11 page
Scalar Hair of Global Defect and Black Brane World
We consider a complex scalar field in (p+3)-dimensional bulk with a negative
cosmological constant and study global vortices in two extra-dimensions. We
reexamine carefully the coupled scalar and Einstein equations, and show that
the boundary value of scalar amplitude at infinity of the extra-dimensions
should be smaller than vacuum expectation value. The brane world has a
cigar-like geometry with an exponentially decaying warp factor and a flat thick
p-brane is embedded. Since a coordinate transformation identifies the obtained
brane world as a black p-brane world bounded by a horizon, this strange
boundary condition of the scalar amplitude is understood as existence of a
short scalar hair.Comment: 26 pages, 2 figure
Adiabatic quantum pumping of a desired ratio of spin current to charge current
We present a prescription for generating pure spin current or spin selective
current, based on adiabatic quantum pumping in a tight-binding model of a one
dimensional conductor. A formula for the instantaneous pumped current is
derived without introducing the scattering matrix. Our calculations indicate
that some pumping cycles produce the maximum value 2 of pumped spin while
others reverse the direction of current as a result of small alterations of the
pumping cycle. We find pumping cycles which produce essentially any ratio of
spin current to charge current.Comment: 8 pages, 7 figures, to be published in PR
Localized gravity and mass hierarchy in D=6 with the Gauss-Bonnet term
We obtain the localized gravity on the intersection of two orthogonal
non-solitonic or solitonic 4-branes in D=6 in the presence of the Gauss-Bonnet
term. The tension of the intersection is allowed to exist unlike the case
without the Gauss-Bonnet term. We show that gravity could be confined to the
solitonic 4-branes for a particular choice of the Gauss-Bonnet coupling. If the
extra dimensions are compactified with the orbifold
symmetry, the mass hierarchy between the Planck scale and the weak scale can be
explained by putting our universe at the TeV intersection of positive tension
located at the orbifold fixed point.Comment: Latex file of 12 page
Path integral formulation of Hodge duality on the brane
In the warped compactification with a single Randall-Sundrum brane, a
puzzling claim has been made that scalar fields can be bound to the brane but
their Hodge dual higher-rank anti-symmetric tensors cannot. By explicitly
requiring the Hodge duality, a prescription to resolve this puzzle was recently
proposed by Duff and Liu. In this note, we implement the Hodge duality via path
integral formulation in the presence of the background gravity fields of warped
compactifications. It is shown that the prescription of Duff and Liu can be
naturally understood within this framework.Comment: 7 pages, LaTe
Annealing Effect for Supersolid Fraction in He
We report on experimental confirmation of the non-classical rotational
inertia (NCRI) in solid helium samples originally reported by Kim and Chan. The
onset of NCRI was observed at temperatures below ~400 mK. The ac velocity for
initiation of the NCRI suppression is estimated to be ~10 m/sec. After an
additional annealing of the sample at K for 12 hours, ~ 10% relative
increase of NCRI fraction was observed. Then after repeated annealing with the
same conditions, the NCRI fraction was saturated. It differs from Reppy's
observation on a low pressure solid sample.Comment: to be published in J. of Low Temp. Phys. (QFS2006 proceedings
orbifold compactifications in with Gauss-Bonnet term
We present a general setup for junctions of semi-infinite 4-branes in
with the Gauss-Bonnet term. The 3-brane tension at the junction of 4-branes can
be nonzero. Using the brane junctions as the origin of the discrete
rotation symmetry, we identify 3-brane tensions at three fixed points of the
orbifold in terms of the 4-brane tensions. As a result, the three
3-brane tensions can be simultaneously positive, which enables us to explain
the mass hierarchy by taking one of two branes apart from the hidden brane as
the visible brane, and hence does not introduce a severe cosmological problem.Comment: Latex file of 20 pages including 2 figure
Prevention or Control: Optimal Government Policies for Invasive Species Management
We present a conceptual, but empirically applicable, model for determining the optimal allocation of resources between exclusion and control activities for managing an invasive species with an uncertain discovery time. This model is used to investigate how to allocate limited resources between activities before and after the first discovery of an invasive species and the effects of the characteristics of an invasive species on limited resource allocation. The optimality conditions show that it is economically efficient to spend a larger share of outlays for exclusion activities before, rather than after, a species is first discovered, up to a threshold point. We also find that, after discovery, more exclusionary measures and fewer control measures are optimal, when the pest population is less than a threshold. As the pest population increases beyond this threshold, the exclusionary measures are no longer optimal. Finally, a comparative dynamic analysis indicates that the efficient level of total expenditures on preventive and control measures decreases with the level of the invasive species stock and increases with the intrinsic population growth rate, the rate of additional discoveries avoided, and the maximum possible pest population.invasive species, exclusion, control, eradication, public expenditures, Environmental Economics and Policy, Resource /Energy Economics and Policy,
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