73 research outputs found
Double Wick rotating Green-Schwarz strings
Via an appropriate field redefinition of the fermions, we find a set of
conditions under which light cone gauge fixed world sheet theories of strings
on two different backgrounds are related by a double Wick rotation. These
conditions take the form of a set of transformation laws for the background
fields, complementing a set of transformation laws for the metric and B field
we found previously with a set for the dilaton and RR fields, and are
compatible with the supergravity equations of motion. Our results prove that at
least to second order in fermions, the AdS_5 x S^5 mirror model which plays an
important role in the field of integrability in AdS/CFT, represents a string on
`mirror AdS_5 x S^5', the background that follows from our transformations. We
discuss analogous solutions for AdS_3 x S^3 x T^4 and AdS_2 x S^2 x T^6. The
main ingredient in our derivation is the light cone gauge fixed action for a
string on an (almost) completely generic background, which we explicitly derive
to second order in fermions.Comment: v2, updated discussion on target space interpretation, elaborated
discussion on minor points, content matches published version, 28 pages, 3
figure
Puzzles of eta-deformed AdS_5 x S^5
We derive the part of the Lagrangian for the sigma model on the eta-deformed
AdS_5 x S^5 space which is quadratic in fermions and has the full dependence on
bosons. We then show that there exists a field redefinition which brings the
corresponding Lagrangian to the standard form of type IIB Green-Schwarz
superstring. Reading off the corresponding RR couplings, we observe that they
fail to satisfy the supergravity equations of motion, despite the presence of
kappa-symmetry. However, in a special scaling limit our solution reproduces the
supergravity background found by Maldacena and Russo. Further, using the
fermionic Lagrangian, we compute a number of new matrix elements of the tree
level world-sheet scattering matrix. We then show that after a unitary
transformation on the basis of two-particle states which is not one-particle
factorisable, the corresponding T-matrix factorises into two equivalent parts.
Each part satisfies the classical Yang-Baxter equation and coincides with the
large tension limit of the q-deformed S-matrix.Comment: 59 pages, 1 figure, v2: minor correction
Limiting Geometries of Two Circular Maldacena-Wilson Loop Operators
We further analyze a recent perturbative two-loop calculation of the
expectation value of two axi-symmetric circular Maldacena-Wilson loops in N=4
gauge theory. Firstly, it is demonstrated how to adapt the previous calculation
of anti-symmetrically oriented circles to the symmetric case. By shrinking one
of the circles to zero size we then explicitly work out the first few terms of
the local operator expansion of the loop. Our calculations explicitly
demonstrate that circular Maldacena-Wilson loops are non-BPS observables
precisely due to the appearance of unprotected local operators. The latter
receive anomalous scaling dimensions from non-ladder diagrams. Finally, we
present new insights into a recent conjecture claiming that coincident circular
Maldacena-Wilson loops are described by a Gaussian matrix model. We report on a
novel, supporting two-loop test, but also explain and illustrate why the
existing arguments in favor of the conjecture are flawed.Comment: 16 pages, numerous figure
Four-point functions of all-different-weight chiral primary operators in the supergravity approximation
Recently a Mellin-space formula was conjectured for the form of correlation
functions of BPS operators in planar SYM in the strong 't
Hooft coupling limit. In this work we report on the computation of two
previously unknown four-point functions of operators with weights and , from the effective type-IIB supergravity
action using AdS/CFT. These correlators are novel: they are the first
correlators with all-different weights and in particular
is the first next-next-next-to-extremal correlator to ever have been computed.
We also present simplifications of the known algorithm, without which these
computations could not have been executed without considerable computer power.
The main simplifications we found are present in the computation of the
exchange Lagrangian and in the computation of tensors. After bringing our
results in the appropriate form we successfully corroborate the recently
conjectured formula.Comment: 20+23 pages, 3 figures; v2: published versio
Five-loop Konishi from the Mirror TBA
We use the Thermodynamic Bethe Ansatz equations for the AdS_5 \times S^5
mirror model to derive the five-loop anomalous dimension of the Konishi
operator. We show numerically that the corresponding result perfectly agrees
with the one recently obtained via the generalized Luscher formulae. This
constitutes an important test of the AdS/CFT TBA system.Comment: 14 pages, 2 figures, v2: published versio
Four-point functions of 1/2-BPS operators of any weights in the supergravity approximation
We present the computation of all the correlators of 1/2-BPS operators in
SYM with weights up to 8 as well as some very high-weight
correlation functions from the effective supergravity action. The computation
is done by implementing the recently developed simplified algorithm in
combination with the harmonic polynomial formalism. We provide a database of
these results attached to this publication and additionally check for almost
all of the functions in this database that they agree with the conjecture on
their Mellin-space form.Comment: 6 pages, database included; v2: database extended, appendix adde
Superstrings on AdS_4 x CP^3 as a Coset Sigma-model
According to the recent proposal by Aharony, Bergman, Jafferis and Maldacena
the N=6 supersymmetric Chern-Simons theory in three dimensions has a 't Hooft
limit whose holographic dual is described by type IIA superstings on AdS_4 x
CP^3 background. We argue that the Green-Schwarz action for type IIA string
theory on AdS_4 x CP^3 with kappa-symmetry partially fixed can be understood as
a coset sigma-model on the same space supplied with a proper Wess-Zumino term.
We construct the corresponding sigma-model Lagrangian and show that it is
invariant under a local fermionic symmetry which for generic bosonic string
configurations allows one to remove 8 out of 24 fermionic degrees of freedom.
The remaining 16 fermions together with their bosonic partners should describe
the physical content of AdS_4 x CP^3 superstring. As further evidence, we
demonstrate that in the plane-wave limit the quadratic action arising from our
model reproduces the one emerging from the type IIA superstring. The coset
sigma-model is classically integrable which opens up the possibility to
investigate its dynamics in a way very similar to the case of AdS_5 x S^5
superstrings.Comment: 29 pages; v2: typos corrected, refs adde
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