4,925 research outputs found
Near-flat space limit and Einstein manifolds
We study the near-flat space limit for strings on AdS(5)xM(5), where the
internal manifold M(5) is equipped with a generic metric with U(1)xU(1)xU(1)
isometry. In the bosonic sector, the limiting sigma model is similar to the one
found for AdS(5)xS(5), as the global symmetries are reduced in the most general
case. When M(5) is a Sasaki-Einstein space like T(1,1), Y(p,q) and L(p,q,r),
whose dual CFT's have N=1 supersymmetry, the near-flat space limit gives the
same bosonic sector of the sigma model found for AdS(5)xS(5). This indicates
the generic presence of integrable subsectors in AdS/CFT.Comment: 30 pages, 1 figur
Strings on the deformed T^{1,1}: giant magnon and single spike solutions
In this paper we find giant magnon and single spike string solutions in a
sector of the gamma-deformed conifold. We examine the dispersion relations and
find a behavior analogous to the undeformed case. The transcendental functional
relations between the conserved charges are shifted by certain gamma-dependent
term. The latter is proportional to the total momentum and thus qualitatively
different from known cases.Comment: 35 pages, no figure
A Test of the AdS/CFT Correspondence Using High-Spin Operators
In two remarkable recent papers, hep-th/0610248 and hep-th/0610251, the
complete planar perturbative expansion was proposed for the universal function
of the coupling, f(g), appearing in the dimensions of high-spin operators of
the N=4 SYM theory. We study numerically the integral equation derived in
hep-th/0610251, which implements a resummation of the perturbative expansion,
and find a smooth function that approaches the asymptotic form predicted by
string theory. In fact, the two leading terms at strong coupling match with
high accuracy the results obtained for the semiclassical folded string spinning
in . This constitutes a remarkable confirmation of the AdS/CFT
correspondence for high-spin operators, and equivalently for the cusp anomaly
of a Wilson loop. We also make a numerical prediction for the third term in the
strong coupling series.Comment: 11 pages, 1 figure; added references, corrected typo
On the pulsating strings in AdS_5 x T^{1,1}
We study the class of pulsating strings in AdS_5 x T^{1,1}. Using a
generalized ansatz for pulsating string configurations we find new solutions of
this class. Further we semiclassically quantize the theory and obtain the first
correction to the energy. The latter, due to AdS/CFT correspondence, is
supposed to give the anomalous dimensions of operators in the dual N=1
superconformal gauge field theory.Comment: 12 pages, improvements made, references adde
Zonotopes and four-dimensional superconformal field theories
The a-maximization technique proposed by Intriligator and Wecht allows us to
determine the exact R-charges and scaling dimensions of the chiral operators of
four-dimensional superconformal field theories. The problem of existence and
uniqueness of the solution, however, has not been addressed in general setting.
In this paper, it is shown that the a-function has always a unique critical
point which is also a global maximum for a large class of quiver gauge theories
specified by toric diagrams. Our proof is based on the observation that the
a-function is given by the volume of a three dimensional polytope called
"zonotope", and the uniqueness essentially follows from Brunn-Minkowski
inequality for the volume of convex bodies. We also show a universal upper
bound for the exact R-charges, and the monotonicity of a-function in the sense
that a-function decreases whenever the toric diagram shrinks. The relationship
between a-maximization and volume-minimization is also discussed.Comment: 29 pages, 15 figures, reference added, typos corrected, version
published in JHE
On the pp-wave limit and the BMN structure of new Sasaki-Einstein spaces
We construct the pp-wave string associated with the Penrose limit of
and families of Sasaki-Einstein geometries. We identify
in the dual quiver gauge theories the chiral and the non-chiral operators that
correspond to the ground state and the first excited states. We present an
explicit identification in a prototype model of .Comment: 21 pages, JHEP format, 5 figures, acknowledgement correcte
Small x Behavior of Parton Distributions from the Observed Froissart Energy Dependence of the Deep Inelastic Scattering Cross Section
We fit the reduced cross section for deep-inelastic electron scattering data
to a three parameter ln^2 s fit, A + beta ln^2 (s/s_0), where s= [Q^2/x] (1-x)
+ m^2, and Q^2 is the virtuality of the exchanged photon. Over a wide range in
Q^2 (0.11 < Q^2 < 1200 GeV^2) all of the fits satisfy the logarithmic energy
dependence of the Froissart bound. We can use these results to extrapolate to
very large energies and hence to very small values of Bjorken x -- well beyond
the range accessible experimentally. As Q^2 --> infinity, the structure
function F_2^p(x, Q^2) exhibits Bjorken scaling, within experimental errors. We
obtain new constraints on the behavior of quark and antiquark distribution
functions at small x.Comment: 10 pages, 2 figure
Effects of pasture on carcass composition in Cinta Senese pig
The trial was performed to investigate on the effects of different periods of grass pasture in fattening Cinta Senese pigs; growth performances, carcass characteristics and meat quality were studied. Control group was reared in paddock and fed concentrate, while experimental group grazed on grass pasture with an integration of 1.4 kg/pig/d of concentrate. Initial live weight was not different between the two groups and individual weights were periodically recorded. Animals were slaughtered from 36 to 160 days from the trial beginning. Carcass weight, body measures, backfat thickness, pH45 and pH24 were recorded. After 24 hours of refrigeration, each carcass was dissected into lean, fat and bone cuts. Results didn't show differences between the two groups, revealing that Cinta Senese pigs can profitably utilize pasture on grass even in fattening period
China’s Foreign Policy: The Emergence of a Great Power
This volume explains China’s foreign policy from the perspective of its historical recovery after 1949 and the country’s subsequent rise as a great power, including its transformation into a global power. It also illuminates how China has, in tandem with its rise, developed an increasing array of political, economic, ‘sharp power’ and military capabilities that is helping it to further its increasingly expansive foreign policy objectives. The volume examines two key questions: What have been the implications of China’s rise for its foreign policy? And how has an increasingly powerful and confident China used a range of foreign policy instruments to pursue its expanding national interests in Asia and beyond? The volume is divided into three parts, covering the conceptualization and drivers of China’s foreign policy, China’s relations with the world, and the instruments of China’s foreign policy, namely its economic power, military capabilities and its ‘sharp power’ manipulation of information and relationships. It will be of interest to academics, students and researchers interested in understanding China’s role in world politics
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