1,566 research outputs found
Notes on the ambient approach to boundary values of AdS gauge fields
The ambient space of dimension d+2 allows to formulate both fields on
AdS(d+1) and conformal fields in d dimensions such that the symmetry algebra
o(d,2) is realized linearly. We elaborate an ambient approach to the boundary
analysis of gauge fields on anti de Sitter spacetime. More technically, we use
its parent extension where fields are still defined on AdS or conformal space
through arbitrary intrinsic coordinates while the ambient construction works in
the target space. In this way, a manifestly local and o(d,2)-covariant
formulation of the boundary behaviour of massless symmetric tensor gauge fields
on AdS(d+1) spacetime is obtained. As a byproduct, we identify some useful
ambient formulation for Fronsdal fields, conformal currents and shadow fields
along with a concise generating-function formulation of the Fradkin-Tseytlin
conformal fields somewhat similar to the one obtained by Metsaev. We also show
how this approach extends to more general gauge theories and discuss its
relation to the unfolded derivation of the boundary dynamics recently proposed
by Vasiliev.Comment: Slightly expanded version of the invited contribution to the J.Phys.A
special volume on "Higher Spin Theories and AdS/CFT" edited by Matthias
Gaberdiel and Mikhail Vasiliev; version 2: addition of 2 references, some
comparisons with the standard AdS/CFT framework and comments on the scalar
singleton cas
Consistent interactions of dual linearized gravity in D=5: couplings with a topological BF model
Under some plausible assumptions, we find that the dual formulation of
linearized gravity in D=5 can be nontrivially coupled to the topological BF
model in such a way that the interacting theory exhibits a deformed gauge
algebra and some deformed, on-shell reducibility relations. Moreover, the
tensor field with the mixed symmetry (2,1) gains some shift gauge
transformations with parameters from the BF sector.Comment: 63 pages, accepted for publication in Eur. Phys. J.
Surface charges and dynamical Killing tensors for higher spin gauge fields in constant curvature spaces
In the context of massless higher spin gauge fields in constant curvature
spaces, we compute the surface charges which generalize the electric charge for
spin one, the color charges in Yang-Mills theories and the energy-momentum and
angular momentum for asymptotically flat gravitational fields. We show that
there is a one-to-one map from surface charges onto divergence free Killing
tensors. These Killing tensors are computed by relating them to a cohomology
group of the first quantized BRST model underlying the Fronsdal action.Comment: 21 pages Latex file, references and comment adde
Higher spin interactions with scalar matter on constant curvature spacetimes: conserved current and cubic coupling generating functions
Cubic couplings between a complex scalar field and a tower of symmetric
tensor gauge fields of all ranks are investigated on any constant curvature
spacetime of dimension d>2. Following Noether's method, the gauge fields
interact with the scalar field via minimal coupling to the conserved currents.
A symmetric conserved current, bilinear in the scalar field and containing up
to r derivatives, is obtained for any rank r from its flat spacetime
counterpart in dimension d+1, via a radial dimensional reduction valid
precisely for the mass-square domain of unitarity in (anti) de Sitter spacetime
of dimension d. The infinite collection of conserved currents and cubic
vertices are summarized in a compact form by making use of generating functions
and of the Weyl/Wigner quantization on constant curvature spaces.Comment: 35+1 pages, v2: two references added, typos corrected, enlarged
discussions in Subsection 5.2 and in Conclusion, to appear in JHE
Spin 3 cubic vertices in a frame-like formalism
Till now most of the results on interaction vertices for massless higher spin
fields were obtained in a metric-like formalism using completely symmetric
(spin-)tensors. In this, the Lagrangians turn out to be very complicated and
the main reason is that the higher the spin one want to consider the more
derivatives one has to introduce. In this paper we show that such
investigations can be greatly simplified if one works in a frame-like
formalism. As an illustration we consider massless spin 3 particle and
reconstruct a number of vertices describing its interactions with lower spin 2,
1 and 0 ones. In all cases considered we give explicit expressions for the
Lagrangians and gauge transformations and check that the algebra of gauge
transformations is indeed closed.Comment: 17 pades, no figure
Higher-Spin Fermionic Gauge Fields and Their Electromagnetic Coupling
We study the electromagnetic coupling of massless higher-spin fermions in
flat space. Under the assumptions of locality and Poincare invariance, we
employ the BRST-BV cohomological methods to construct consistent
parity-preserving off-shell cubic 1-s-s vertices. Consistency and
non-triviality of the deformations not only rule out minimal coupling, but also
restrict the possible number of derivatives. Our findings are in complete
agreement with, but derived in a manner independent from, the
light-cone-formulation results of Metsaev and the string-theory-inspired
results of Sagnotti-Taronna. We prove that any gauge-algebra-preserving vertex
cannot deform the gauge transformations. We also show that in a local theory,
without additional dynamical higher-spin gauge fields, the non-abelian vertices
are eliminated by the lack of consistent second-order deformations.Comment: 44 pages; references added, minor changes made, to appear in JHE
Higher-Spin Interactions: four-point functions and beyond
In this work we construct an infinite class of four-point functions for
massless higher-spin fields in flat space that are consistent with the gauge
symmetry. In the Lagrangian picture, these reflect themselves in a peculiar
non-local nature of the corresponding non-abelian higher-spin couplings implied
by the Noether procedure that starts from the fourth order. We also comment on
the nature of the colored spin-2 excitation present both in the open string
spectrum and in the Vasiliev system, highlighting how some aspects of String
Theory appear to reflect key properties of Field Theory that go beyond its low
energy limit. A generalization of these results to n-point functions, fermions
and mixed-symmetry fields is also addressed.Comment: 66 pages, 10 figures, 1 table, LaTex. Several statements clarified.
Final version to appear in JHE
A class of six-dimensional conformal field theories
We describe a class of six-dimensional conformal field theories that have
some properties in common with and possibly are related to a subsector of the
tensionless string theories. The latter theories can for example give rise to
four-dimensional superconformal Yang-Mills theories upon
compactification on a two-torus. Just like the tensionless string theories, our
theories have an -classification, but no other discrete or continuous
parameters. The Hilbert space carries an irreducible representation of the same
Heisenberg group that appears in the tensionless string theories, and the
`Wilson surface' observables obey the same superselection rules. When
compactified on a two-torus, they have the same behaviour under -duality as
super Yang-Mills theory. Our theories are natural generalizations of the
two-form with self-dual field strength that is part of the world-volume theory
of a single five-brane in -theory, and the theory can in fact be
seen as arising from non-interacting chiral two-forms by factoring out the
collective `center of mass' degrees of freedom.Comment: 8 pages. More pedagogical presentation, added section on relationship
to d = 4 Yang-Mills theor
Classification of non-Riemannian doubled-yet-gauged spacetime
Assuming covariant fields as the `fundamental' variables,
Double Field Theory can accommodate novel geometries where a Riemannian metric
cannot be defined, even locally. Here we present a complete classification of
such non-Riemannian spacetimes in terms of two non-negative integers,
, . Upon these backgrounds, strings become
chiral and anti-chiral over and directions respectively, while
particles and strings are frozen over the directions. In
particular, we identify as Riemannian manifolds, as
non-relativistic spacetime, as Gomis-Ooguri non-relativistic string,
as ultra-relativistic Carroll geometry, and as Siegel's
chiral string. Combined with a covariant Kaluza-Klein ansatz which we further
spell, leads to Newton-Cartan gravity. Alternative to the conventional
string compactifications on small manifolds, non-Riemannian spacetime such as
, may open a new scheme of the dimensional reduction from ten to
four.Comment: 1+41 pages; v2) Refs added; v3) Published version; v4) Sign error in
(2.51) correcte
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