25,634 research outputs found
Massive higher spins and holography
We review recent progress towards the understanding of higher spin gauge
symmetry breaking in AdS space from a holographic vantage point. According to
the AdS/CFT correspondence, N=4 SYM theory at vanishing coupling constant
should be dual to a theory in AdS which exhibits higher spin gauge symmetry
enhancement. When the SYM coupling is non-zero, all but a handful of HS
currents are violated by anomalies, and correspondingly local higher spin
symmetry in the bulk gets spontaneously broken. In agreement with previous
results and holographic expectations, we find that, barring one notable
exception (spin 1 eating spin 0), the Goldstone modes responsible for HS
symmetry breaking in AdS have non-vanishing mass even in the limit in which the
gauge symmetry is restored. We show that spontaneous breaking a' la
Stueckelberg implies that the mass of the relevant spin s'=s-1 Goldstone field
is exactly the one predicted by the correspondence.Comment: 8 pages, talk presented by M.B. at the "Fourth Meeting on Constrained
Dynamics and Quantum gravity" held in Cala Gonone (Sardinia, Italy),
September 12-16, 200
SL(2,Z) Multiplets in N=4 SYM Theory
We discuss the action of SL(2,Z) on local operators in D=4, N=4 SYM theory in
the superconformal phase. The modular property of the operator's scaling
dimension determines whether the operator transforms as a singlet, or
covariantly, as part of a finite or infinite dimensional multiplet under the
SL(2,Z) action. As an example, we argue that operators in the Konishi multiplet
transform as part of a (p,q) PSL(2,Z) multiplet. We also comment on the
non-perturbative local operators dual to the Konishi multiplet.Comment: 14 pages, harvmac; v2: published version with minor change
String amplitudes in the Hpp-wave limit of AdS3xS3
We compute string amplitudes on pp-waves supported by NS-NS 3-form fluxes and
arising in the Penrose limit of AdS3xS3xM. We clarify the role of the
non-chiral accidental SU(2) symmetry of the background. We comment on the
extension of our results to the superstring and propose a holographic formula
in the BMN limit of the AdS3/CFT2 correspondence valid for any correlator.Comment: Latex,no figures, 47 p
Precision Spectroscopy and Higher Spin symmetry in the ABJM model
We revisit Kaluza-Klein compactification of 11-d supergravity on S^7/Z_k
using group theory techniques that may find application in other flux vacua
with internal coset spaces. Among the SO(2) neutral states, we identify
marginal deformations and fields that couple to the recently discussed
world-sheet instanton of Type IIA on CP^3. We also discuss charged states, dual
to monopole operators, and the Z_k projection of the Osp(4|8) singleton and its
tensor products. In particular, we show that the doubleton spectrum may account
for N=6 higher spin symmetry enhancement in the limit of vanishing 't Hooft
coupling in the boundary Chern-Simons theory.Comment: 44 page
Correlation functions in a cascading N=1 gauge theory from supergravity
We study fluctuations around the warped conifold supergravity solution of
Klebanov and Tseytlin [hep-th/0002159], known to be dual to a cascading N=1
gauge theory. Although this supergravity background is not asymptotically AdS,
corresponding to a non-conformal field theory, it is possible to apply the
usual methods of AdS/CFT duality to extract the high energy behavior of field
theory correlators by solving linearized equations of motion for fluctuations
around the background. We consider the Goldstone vector dual to the anomalous
R-symmetry current and compute its mass, which exactly matches the general
prediction of [hep-th/0009156]. We find the high energy 2-point functions for
the R-current and two other vectors. As expected, the R-current 2-point
function has a longitudinal part because R-symmetry is broken. We also
calculate the high energy 2-point function of the energy-momentum tensor from
fluctuations of modes in the graviton sector. This 2-point function has a trace
part corresponding to broken conformal symmetry.Comment: JHEP, 29 page
The EPRL intertwiners and corrected partition function
Do the SU(2) intertwiners parametrize the space of the EPRL solutions to the
simplicity constraint? What is a complete form of the partition function
written in terms of this parametrization? We prove that the EPRL map is
injective for n-valent vertex in case when it is a map from SO(3) into
SO(3)xSO(3) representations. We find, however, that the EPRL map is not
isometric. In the consequence, in order to be written in a SU(2) amplitude
form, the formula for the partition function has to be rederived. We do it and
obtain a new, complete formula for the partition function. The result goes
beyond the SU(2) spin-foam models framework.Comment: RevTex4, 15 pages, 5 figures; theorem of injectivity of EPRL map
correcte
Simplifying one-loop amplitudes in superstring theory
We show that 4-point vector boson one-loop amplitudes, computed in ref.[1] in
the RNS formalism, around vacuum configurations with open unoriented strings,
preserving at least N=1 SUSY in D=4, satisfy the correct supersymmetry Ward
identities, in that they vanish for non MHV configurations (++++) and (-+++).
In the MHV case (--++) we drastically simplify their expressions. We then study
factorisation and the limiting IR and UV behaviour and find some unexpected
results. In particular no massless poles are exposed at generic values of the
modular parameter. Relying on the supersymmetric properties of our bosonic
amplitudes, we extend them to manifestly supersymmetric super-amplitudes and
compare our results with those obtained in the D=4 hybrid formalism, pointing
out difficulties in reconciling the two approaches for contributions from N=1,2
sectors.Comment: 38 pages plus appendice
Wilson-'t Hooft operators and the theta angle
We consider -dimensional Yang-Mills theory on a
space-time with a compact spatial direction, and prove the following result:
Under a continuous increase of the theta angle , a 't
Hooft operator associated with a closed spatial curve that
winds around the compact direction undergoes a monodromy . The new 't Hooft operator transforms
under large gauge transformations in the same way as the product , where is the Wilson operator associated with the curve
and the fundamental representation of SU(N).Comment: 7 page
D-brane Instantons on the T^6/Z_3 orientifold
We give a detailed microscopic derivation of gauge and stringy instanton
generated superpotentials for gauge theories living on D3-branes at
Z_3-orientifold singularities. Gauge instantons are generated by D(-1)-branes
and lead to Affleck, Dine and Seiberg (ADS) like superpotentials in the
effective N=1 gauge theories with three generations of bifundamental and
anti/symmetric matter. Stringy instanton effects are generated by Euclidean
ED3-branes wrapping four-cycles on T^6/\Z_3. They give rise to Majorana masses
in one case and non-renormalizable superpotentials for the other cases. Finally
we determine the conditions under which ADS like superpotentials are generated
in N=1 gauge theories with adjoints, fundamentals, symmetric and antisymmetric
chiral matter.Comment: 31 pages, no figure
On the spectrum of AdS/CFT beyond supergravity
We test the spectrum of string theory on AdS_5 x S^5 derived in
hep-th/0305052 against that of single-trace gauge invariant operators in free
N=4 super Yang-Mills theory. Masses of string excitations at critical tension
are derived by extrapolating plane-wave frequencies at g_{YM}=0 down to finite
J. On the SYM side, we present a systematic description of the spectrum of
single-trace operators and its reduction to PSU(2,2|4) superconformal primaries
via a refined Eratostenes' supersieve. We perform the comparison of the
resulting SYM/string spectra of charges and multiplicities order by order in
the conformal dimension \Delta up to \Delta=10 and find perfect agreement.
Interestingly, the SYM/string massive spectrum exhibits a hidden symmetry
structure larger than expected, with bosonic subgroup SO(10,2) and thirty-two
supercharges.Comment: 28 pages, LaTeX2
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