4,313 research outputs found
Continuous distributions of D3-branes and gauged supergravity
States on the Coulomb branch of N=4 super-Yang-Mills theory are studied from
the point of view of gauged supergravity in five dimensions. These
supersymmetric solutions provide examples of consistent truncation from type
IIB supergravity in ten dimensions. A mass gap for states created by local
operators and perfect screening for external quarks arise in the supergravity
approximation. We offer an interpretation of these surprising features in terms
of ensembles of brane distributions.Comment: 19 pages, two figures, latex. v2: reference added, small corrections.
v3: corrected unbounded spectrum erro
Boundary Terms and Three-Point Functions: An AdS/CFT Puzzle Resolved
superconformal field theories, such as the ABJM theory at
Chern-Simons level or , contain 35 scalar operators
with in the representation of SO(8). The 3-point
correlation function of these operators is non-vanishing, and indeed can be
calculated non-perturbatively in the field theory. But its AdS gravity
dual, obtained from gauged supergravity, has no cubic
couplings in its Lagrangian, where is the bulk dual of . So conventional Witten diagrams cannot furnish the field theory
result. We show that the extension of bulk supersymmetry to the AdS
boundary requires the introduction of a finite counterterm that does
provide a perfect match to the 3-point correlator. Boundary supersymmetry also
requires infinite counterterms which agree with the method of holographic
renormalization. The generating functional of correlation functions of the
operators is the Legendre transform of the on-shell action, and the
supersymmetry properties of this functional play a significant role in our
treatment.Comment: 67 page
Renormalization Group Flows from Holography--Supersymmetry and a c-Theorem
We obtain first order equations that determine a supersymmetric kink solution
in five-dimensional N=8 gauged supergravity. The kink interpolates between an
exterior anti-de Sitter region with maximal supersymmetry and an interior
anti-de Sitter region with one quarter of the maximal supersymmetry. One eighth
of supersymmetry is preserved by the kink as a whole. We interpret it as
describing the renormalization group flow in N=4 super-Yang-Mills theory broken
to an N=1 theory by the addition of a mass term for one of the three adjoint
chiral superfields. A detailed correspondence is obtained between fields of
bulk supergravity in the interior anti-de Sitter region and composite operators
of the infrared field theory. We also point out that the truncation used to
find the reduced symmetry critical point can be extended to obtain a new N=4
gauged supergravity theory holographically dual to a sector of N=2 gauge
theories based on quiver diagrams.
We consider more general kink geometries and construct a c-function that is
positive and monotonic if a weak energy condition holds in the bulk gravity
theory. For even-dimensional boundaries, the c-function coincides with the
trace anomaly coefficients of the holographically related field theory in
limits where conformal invariance is recovered.Comment: 56 pages, three figures, harvmac. v2: improved referencing, corrected
discussion of energy conditions. v3: one more reference fixe
BVRI photometry of 53 unusual asteroids
We present the results of BVRI photometry and classification of 53 unusual
asteroids, including 35 near-Earth asteroids (NEAs), 6 high
eccentricity/inclination asteroids, and 12 recently-identified asteroid-pair
candidates. Most of these asteroids were not reportedly classified prior to
this work. For the few asteroids that have been previously studied, the results
are generally in rough agreement. In addition, we merge the results from
several photometric/spectroscopic surveys to create a largest-ever sample with
449 spectrally classified NEAs for statistical analysis. We identify a
"transition point" of the relative number of C/X-like and S-like NEAs at
H~18D~1km with confidence level at ~95% or higher. We find that the
C/X-like:S-like ratio for 18<=H<22 is about two times higher than that of H<18
(0.33+/-0.04 versus 0.17+/-0.02), virtually supporting the hypothesis that
smaller NEAs generally have less weathered surface (therefore, less reddish
appearance) caused by younger collision ages.Comment: 18 pages, 9 table
When and where do you want to hide? Recommendation of location privacy preferences with local differential privacy
In recent years, it has become easy to obtain location information quite
precisely. However, the acquisition of such information has risks such as
individual identification and leakage of sensitive information, so it is
necessary to protect the privacy of location information. For this purpose,
people should know their location privacy preferences, that is, whether or not
he/she can release location information at each place and time. However, it is
not easy for each user to make such decisions and it is troublesome to set the
privacy preference at each time. Therefore, we propose a method to recommend
location privacy preferences for decision making. Comparing to existing method,
our method can improve the accuracy of recommendation by using matrix
factorization and preserve privacy strictly by local differential privacy,
whereas the existing method does not achieve formal privacy guarantee. In
addition, we found the best granularity of a location privacy preference, that
is, how to express the information in location privacy protection. To evaluate
and verify the utility of our method, we have integrated two existing datasets
to create a rich information in term of user number. From the results of the
evaluation using this dataset, we confirmed that our method can predict
location privacy preferences accurately and that it provides a suitable method
to define the location privacy preference
X-ray Polarization Signatures of Compton Scattering in Magnetic Cataclysmic Variables
Compton scattering within the accretion column of magnetic cataclysmic
variables (mCVs) can induce a net polarization in the X-ray emission. We
investigate this process using Monte Carlo simulations and find that
significant polarization can arise as a result of the stratified flow structure
in the shock-ionized column. We find that the degree of linear polarization can
reach levels up to ~8% for systems with high accretion rates and low
white-dwarf masses, when viewed at large inclination angles with respect to the
accretion column axis. These levels are substantially higher than previously
predicted estimates using an accretion column model with uniform density and
temperature. We also find that for systems with a relatively low-mass white
dwarf accreting at a high accretion rate, the polarization properties may be
insensitive to the magnetic field, since most of the scattering occurs at the
base of the accretion column where the density structure is determined mainly
by bremsstrahlung cooling instead of cyclotron cooling.Comment: 7 pages, 8 figures, accepted by MNRA
Recommended from our members
Boundary terms and three-point functions: an AdS/CFT puzzle resolved
N= 8 superconformal field theories, such as the ABJM theory at Chern-Simons level k = 1 or 2, contain 35 scalar operators O I J with Δ = 1 in the 35 v representation of SO(8). The 3-point correlation function of these operators is non-vanishing, and indeed can be calculated non-perturbatively in the field theory. But its AdS 4 gravity dual, obtained from gauged N= 8 supergravity, has no cubic A 3 couplings in its Lagrangian, where A IJ is the bulk dual of O I J . So conventional Witten diagrams cannot furnish the field theory result. We show that the extension of bulk supersymmetry to the AdS 4 boundary requires the introduction of a finite A 3 counterterm that does provide a perfect match to the 3-point correlator. Boundary supersymmetry also requires infinite counterterms which agree with the method of holographic renormalization. The generating functional of correlation functions of the Δ = 1 operators is the Legendre transform of the on-shell action, and the supersymmetry properties of this functional play a significant role in our treatment
Cartan Pairs
A new notion of Cartan pairs as a substitute of notion of vector fields in
noncommutative geometry is proposed. The correspondence between Cartan pairs
and differential calculi is established.Comment: 7 pages in LaTeX, to be published in Czechoslovak Journal of Physics,
presented at the 5th Colloquium on Quantum Groups and Integrable Systems,
Prague, June 199
Normal frames for general connections on differentiable fibre bundles
The theory of frames normal for general connections on differentiable bundles
is developed. Links with the existing theory of frames normal for covariant
derivative operators (linear connections) in vector bundles are revealed. The
existence of bundle coordinates normal at a given point and/or along injective
horizontal path is proved. A necessary and sufficient condition of existence of
bundle coordinates normal along injective horizontal mappings is derived.Comment: 24 LaTeX pages. The packages AMS-LaTeX and amsfonts are required. In
version 2 some results are generalized and proved under weaker conditions.
For other papers on the same topic view the "publication" pages at
http://theo.inrne.bas.bg/~bozho
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