4,700 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 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
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
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
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
Gravity duals to deformed SYM theories and Generalized Complex Geometry
We analyze the supersymmetry conditions for a class of SU(2) structure
backgrounds of Type IIB supergravity, corresponding to a specific ansatz for
the supersymmetry parameters. These backgrounds are relevant for the AdS/CFT
correspondence since they are suitable to describe mass deformations or
beta-deformations of four-dimensional superconformal gauge theories. Using
Generalized Complex Geometry we show that these geometries are characterized by
a closed nowhere-vanishing vector field and a modified fundamental form which
is also closed. The vector field encodes the information about the
superpotential and the type of deformation - mass or beta respectively. We also
show that the Pilch-Warner solution dual to a mass-deformation of N =4 Super
Yang-Mills and the Lunin-Maldacena beta-deformation of the same background fall
in our class of solutions.Comment: LaTex, 29 page
Semiclassical strings in Sasaki-Einstein manifolds and long operators in N=1 gauge theories
We study the AdS/CFT relation between an infinite class of 5-d Ypq
Sasaki-Einstein metrics and the corresponding quiver theories. The long BPS
operators of the field theories are matched to massless geodesics in the
geometries, providing a test of AdS/CFT for these cases. Certain small
fluctuations (in the BMN sense) can also be successfully compared. We then go
further and find, using an appropriate limit, a reduced action, first order in
time derivatives, which describes strings with large R-charge. In the field
theory we consider holomorphic operators with large winding numbers around the
quiver and find, interestingly, that, after certain simplifying assumptions,
they can be described effectively as strings moving in a particular metric.
Although not equal, the metric is similar to the one in the bulk. We find it
encouraging that a string picture emerges directly from the field theory and
discuss possible ways to improve the agreement.Comment: 44 pages, LaTeX, 9 figures. v2: References adde
Marginal deformation of N=4 SYM and Penrose limits with continuum spectrum
We study the Penrose limit about a null geodesic with 3 equal angular momenta
in the recently obtained type IIB solution dual to an exactly marginal
-deformation of N=4 SYM. The resulting background has non-trivial NS
3-form flux as well as RR 5- and 3-form fluxes. We quantise the light-cone
Green-Schwarz action and show that it exhibits a continuum spectrum. We show
that this is related to the dynamics of a charged particle moving in a Landau
plane with an extra interaction induced by the deformation. We interpret the
results in the dual N=1 SCFT.Comment: 26 pages, 2 figures; v2: typos corrected, field theory interpretation
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