610 research outputs found
Microscopic Description of Black Rings in AdS/CFT
We discuss some aspects of the recently discovered BPS black ring solutions
in terms of the AdS/CFT correspondence. In the type IIB frame in which the
black ring carries the charges of the D1-D5-P system, we propose a microscopic
description of the rings in the orbifold CFT governing this system. In our
proposal, the CFT effectively splits into two parts: one part captures the
supertube-like properties of the ring, and the other captures the entropy. We
can also understand the black ring entropy by relating the geometry near the
ring to BPS black holes in four dimensions, although this latter approach does
not directly lead to an identification of black rings in terms of the D1-D5-P
CFT.Comment: 18 pages, harvmac. v2 - minor typo
The 4th Industrial Revolution Powered by the Integration of AI, Blockchain, and 5G
The 21st century has introduced the 4th Industrial Revolution, which describes an industrial paradigm shift that alters social, economic, and political environments simultaneously. Innovative technologies such as blockchain, artificial intelligence, and advanced mobile networks power this digital revolution. These technologies provide a unique component that, when integrated, will establish a foundation to drive future innovation. In this paper, we summarize a 2019 Association for Information Systems Americas Conference on Information Systems (AMCIS) panel session where researchers who specialize in these technologies discussed new innovations and their integration. This topic has significant implications to business and academia both as these technologies will disrupt the social, economic, and political landscapes
Comment on "Long-range electrostatic interactions between like-charged colloids: Steric and confinement effects"
In a recent study [Phys. Rev. E 60, 6530 (1999)], Trizac and Raimbault showed
that the effective pair interaction between like charged colloids immersed in a
cylindrically confined electrolyte remains repulsive even when the size of the
micro-ions or the finite longitudinal extension of the confining cylinder are
taken into account. Contrary to their claim, we argue that the case of finite
longitudinal confinement doesn't always generate repulsive interactions and to
illustrate this point we also provide a simple example.Comment: 3 pages, 1 figure. Accepted for publication in Phys. Rev. E 200
Entropy Functions with 5D Chern-Simons terms
In this note we reconsider Sen's entropy function analysis for 5D
supergravity actions containing Chern-Simons terms. The apparent lack of gauge
invariance is usually tackled via a 4D reduction. Here we motivate how a
systematic 5D procedure also works. In doing so, it becomes important to
identify the correct 5D charges. In particular, we perform explicit
calculations for the black ring and 5D black hole. In the black ring analysis,
we find Chern-Simons induced spectral flow shifts emerging out of Sen's
formalism. We find that the entropy function nevertheless remains gauge
invariant and the resulting electric charges are identified as Page charges.
For the black hole too, 5D gauge invariance is confirmed. Our 5D analysis
enables us to fix a mismatch that arose in the electric charges of Goldstein
and Jena's 4D-reduced calculation. Finally we provide an interpretation for the
e^0 - p^0 exchange in the entropy function as an interpolation between black
hole and black ring geometries in Taub-NUT.Comment: 27 page
All Vacuum Near-Horizon Geometries in -dimensions with Commuting Rotational Symmetries
We explicitly construct all stationary, non-static, extremal near horizon
geometries in dimensions that satisfy the vacuum Einstein equations, and
that have commuting rotational symmetries. Our work generalizes
[arXiv:0806.2051] by Kunduri and Lucietti, where such a classification had been
given in . But our method is different from theirs and relies on a
matrix formulation of the Einstein equations. Unlike their method, this matrix
formulation works for any dimension. The metrics that we find come in three
families, with horizon topology , or ,
or quotients thereof. Our metrics depend on two discrete parameters specifying
the topology type, as well as continuous parameters. Not all of
our metrics in seem to arise as the near horizon limits of known
black hole solutions.Comment: 22 pages, Latex, no figures, title changed, references added,
discussion of the parameters specifying solutions corrected, amended to match
published versio
Detecting metal-rich intermediate-age globular clusters in NGC4570 using K-band photometry
âThe original publication is available at www.springerlink.comâ. Copyright Springer. DOI: 10.1007/s10509-009-0093-8Globular cluster systems (GCSs) of most early-type galaxies feature two peaks in their optical colour distributions. Blue-peak globular clusters (GCs) are believed to be old and metal-poor, whereas the ages, metallicities, and the origin of the red-peak GCs are still being debated. We obtained deep K-band photometry and combined it with Hubble Space Telescope observations in g and z to yield a full spectral energy distribution from the optical to the near-infrared. This now allows us to break the ageâmetallicity degeneracy. We used our evolutionary synthesis models galev for star clusters to compute a large grid of models with different metallicities and a wide range of ages. Comparing these models to our observations revealed a large population of intermediate-age (1â3 Gyr) and metal-rich (âsolar-metallicity) GCs, that will give us further insights into the formation history of this galaxy.Peer reviewe
All the supersymmetric solutions of N=1,d=5 ungauged supergravity
We classify the supersymmetric solutions of ungauged N=1 d=5 SUGRA coupled to
vector multiplets and hypermultiplets. All the solutions can be seen as
deformations of solutions with frozen hyperscalars. We show explicitly how the
5-dimensional Reissner-Nordstrom black hole is deformed when hyperscalars are
living on SO(4,1)/SO(4) are turned on, reducing its supersymmetry from 1/2 to
1/8. We also describe in the timelike and null cases the solutions that have
one extra isometry and can be reduced to N=2,d=4 solutions. Our formulae allows
the uplifting of certain N=2,d=4 black holes to N=1,d=5 black holes on KK
monopoles or to pp-waves propagating along black strings.Comment: Some typos fixed and some paragraphs improved. 44 pages, Latex 2e
file, no figures. Version to be published in JHE
First-order flow equations for extremal black holes in very special geometry
We construct interpolating solutions describing single-center static extremal
non-supersymmetric black holes in four-dimensional N=2 supergravity theories
with cubic prepotentials. To this end, we derive and solve first-order flow
equations for rotating electrically charged extremal black holes in a Taub-NUT
geometry in five dimensions. We then use the connection between five- and
four-dimensional extremal black holes to obtain four-dimensional flow equations
and we give the corresponding solutions.Comment: 21 pages. v2: Summary section adde
Holographic multiverse and the measure problem
We discuss the duality, conjectured in earlier work, between the wave
function of the multiverse and a 3D Euclidean theory on the future boundary of
spacetime. In particular, we discuss the choice of the boundary metric and the
relation between the UV cutoff scale xi on the boundary and the hypersurfaces
Sigma on which the wave function is defined in the bulk. We propose that in the
limit of xi going to 0 these hypersurfaces should be used as cutoff surfaces in
the multiverse measure. Furthermore, we argue that in the inflating regions of
spacetime with a slowly varying Hubble rate H the hypersurfaces Sigma are
surfaces of constant comoving apparent horizon (CAH). Finally, we introduce a
measure prescription (called CAH+) which appears to have no pathological
features and coincides with the constant CAH cutoff in regions of slowly
varying H.Comment: A minor change: the discussion of unitarity on p.9 is clarifie
- âŠ