1,497 research outputs found
Strong Evidence In Favor OF The Existence Of S-Matrix For Strings In Plane Waves
Field theories on the plane wave background are considered. We discuss that
for such field theories one can only form 1+1 dimensional freely propagating
wave packets. We analyze tree level four point functions of scalar field theory
as well as scalars coupled to gauge fields in detail and show that these four
point functions are well-behaved so that they can be interpreted as S-matrix
elements for 2 particle 2 particle scattering amplitudes. Therefore, at
least classically, field theories on the plane wave background have S-matrix
formulation.Comment: Latex file, 26 pages, 4 eps figures. v3: In the end of paper there is
a "Note Added" as an update of the result
Non-Abelian BIonic Brane Intersections
We study "fuzzy funnel" solutions to the non-Abelian equations of motion of
the D-string. Our funnel describes n^6/360 coincident D-strings ending on n^3/6
D7-branes, in terms of a fuzzy six-sphere which expands along the string. We
also provide a dual description of this configuration in terms of the world
volume theory of the D7-branes. Our work makes use of an interesting non-linear
higher dimensional generalization of the instanton equations.Comment: 17 pages uses harvmac; v2: small typos corrected, refs adde
Predictions for PP-wave string amplitudes from perturbative SYM
The role of general two-impurity multi-trace operators in the BMN
correspondence is explored. Surprisingly, the anomalous dimensions of all
two-impurity multi-trace BMN operators to order g_2^2\lambda' are completely
determined in terms of single-trace anomalous dimensions. This is due to
suppression of connected field theory diagrams in the BMN limit and this fact
has important implications for some string theory processes on the PP-wave
background. We also make gauge theory predictions for the matrix elements of
the light-cone string field theory Hamiltonian in the two string-two string and
one string-three string sectors.Comment: 46 pages, 12 figures. V3:typos correcte
A Calculation of the plane wave string Hamiltonian from N=4 super-Yang-Mills theory
Berenstein, Maldacena, and Nastase have proposed, as a limit of the strong
form of the AdS/CFT correspondence, that string theory in a particular plane
wave background is dual to a certain subset of operators in the N=4
super-Yang-Mills theory. Even though this is a priori a strong/weak coupling
duality, the matrix elements of the string theory Hamiltonian, when expressed
in gauge theory variables, are analytic in the 't Hooft coupling constant. This
allows one to conjecture that, like the masses of excited string states, these
can be recovered using perturbation theory in Yang-Mills theory.
In this paper we identify the difference between the generator of scale
transformations and a particular U(1) R-symmetry generator as the operator dual
to the string theory Hamiltonian for nonvanishing string coupling. We compute
its matrix elements and find that they agree with the string theory prediction
provided that the state-operator map is modified for nonvanishing string
coupling. We construct this map explicitly and calculate the anomalous
dimensions of the new operators. We identify the component arising from the
modification of the state-operator map with the contribution of the string
theory contact terms to the masses of string states.Comment: 38 pages, Latex; v2: Comparison with string theory changed in light
of corrections to string theory results in hep-th/0206073 v3; state-operator
map modified; Physical interpretation and conclusions unchange
A Novel Long Range Spin Chain and Planar N=4 Super Yang-Mills
We probe the long-range spin chain approach to planar N=4 gauge theory at
high loop order. A recently employed hyperbolic spin chain invented by
Inozemtsev is suitable for the SU(2) subsector of the state space up to three
loops, but ceases to exhibit the conjectured thermodynamic scaling properties
at higher orders. We indicate how this may be bypassed while nevertheless
preserving integrability, and suggest the corresponding all-loop asymptotic
Bethe ansatz. We also propose the local part of the all-loop gauge transfer
matrix, leading to conjectures for the asymptotically exact formulae for all
local commuting charges. The ansatz is finally shown to be related to a
standard inhomogeneous spin chain. A comparison of our ansatz to semi-classical
string theory uncovers a detailed, non-perturbative agreement between the
corresponding expressions for the infinite tower of local charge densities.
However, the respective Bethe equations differ slightly, and we end by refining
and elaborating a previously proposed possible explanation for this
disagreement.Comment: 48 pages, 1 figure. v2, further results added: discussion of the
relationship to an inhomogeneous spin chain, normalization in sec 3 unified,
v3: minor mistakes corrected, published versio
Deconstruction, Lattice Supersymmetry, Anomalies and Branes
We study the realization of anomalous Ward identities in deconstructed
(latticized) supersymmetric theories. In a deconstructed four-dimensional
theory with N=2 supersymmetry, we show that the chiral symmetries only appear
in the infrared and that the anomaly is reproduced in the usual framework of
lattice perturbation theory with Wilson fermions. We then realize the theory on
the world-volume of fractional D-branes on an orbifold. In this brane
realization, we show how deconstructed theory anomalies can be computed via
classical supergravity. Our methods and observations are more generally
applicable to deconstructed/latticized supersymmetric theories in various
dimensions.Comment: 1+27 pages, 2 figures, references adde
Graviton-Scalar Interaction in the PP-Wave Background
We compute the graviton two scalar off-shell interaction vertex at tree level
in Type IIB superstring theory on the pp-wave background using the light-cone
string field theory formalism. We then show that the tree level vertex vanishes
when all particles are on-shell and conservation of p_{+} and p_{-} are
imposed. We reinforce our claim by calculating the same vertex starting from
the corresponding SUGRA action expanded around the pp-wave background in the
light-cone gauge.Comment: 26 pages, harvmac One reference added. A few comments changed in the
introduction. The "cyclic perms." term removed from some equations as
unnecessary and equations (2.38) and (3.19) are corrected accordingl
Open-Closed Duality at Tree Level
We study decay of unstable D-branes in string theory in the presence of
electric field, and show that the classical open string theory results for
various properties of the final state agree with the properties of closed
string states into which the system is expected to decay. This suggests a
duality between tree level open string theory on unstable D-branes and closed
strings at high density.Comment: LaTeX file, 10 page
Extraction of parton distributions from lattice QCD
We review the calculation of moments of both the polarized and unpolarized
parton distribution functions of the nucleon in lattice QCD, and in particular
their extrapolation to the physical region. We also discuss the reconstruction
of the x dependence of the valence quark distributions in the nucleon from a
finite number of lattice moments.Comment: 17 pages, 7 figures, mini-review prepared for Mod. Phys. Lett.
Beta-functions in Yang-Mills Theory from Non-critical String
The renormalization group equations of the Yang-Mills theory are examined in
the non-critical string theory according to the framework of the holography.
Under a simple ansatz for the tachyon, we could find several interesting
solutions which are classified by the value of the tachyon potential at the
vacuum. We show two typical, asymptotic-free solutions which are different in
their infrared behaviors. For both types of solutions, we could obtain
quark-confinement potential from the Wilson-loop. The stability of the tachyon
and the ZigZag symmetry are also discussed for these solutions.Comment: 16 pages, 5 figure
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