976 research outputs found
Scalar Field Corrections to AdS_4 Gravity from Higher Spin Gauge Theory
We compute the complete contribution to the stress-energy tensor in the
minimal bosonic higher spin theory in D=4 that is quadratic in the scalar
field. We find arbitrarily high derivative terms, and that the total sign of
the stress-energy tensor depends on the parity of the scalar field.Comment: 15 pages + appendix (30 pages
Chern-Simons Matter Theories and Higher Spin Gravity
We compute the parity violating three point amplitudes with one scalar leg in
higher spin gravity and compare results with those of Chern-Simons matter
theories. The three-point correlators of the free boson, free fermion, critical
vector model and Gross-Neveu model are reproduced including the dependence on
the Chern-Simons coupling. We also perform a simple test of the modified higher
spin equations proposed in arXiv:1605.02662 [hep-th] and find that the results
are consistent with the AdS/CFT correspondence.Comment: 39 pages; minor corrections and refs adde
Representations of p-brane topological charge algebras
The known extended algebras associated with p-branes are shown to be
generated as topological charge algebras of the standard p-brane actions. A
representation of the charges in terms of superspace forms is constructed. The
charges are shown to be the same in standard/extended superspace formulations
of the action.Comment: 22 pages. Typos fixed, refs added. Minor additions to comments
sectio
Supersymmetric Higher Spin Theories
We revisit the higher spin extensions of the anti de Sitter algebra in four
dimensions that incorporate internal symmetries and admit representations that
contain fermions, classified long ago by Konstein and Vasiliev. We construct
the , Euclidean and Kleinian version of these algebras, as well as the
corresponding fully nonlinear Vasiliev type higher spin theories, in which the
reality conditions we impose on the master fields play a crucial role. The
supersymmetric higher spin theory in , on which we elaborate
further, is included in this class of models. A subset of Konstein-Vasiliev
algebras are the higher spin extensions of the superalgebras
for mod 4 and can be realized using
fermionic oscillators. We tensor the higher superalgebras of the latter kind
with appropriate internal symmetry groups and show that the mod 4
higher spin algebras are isomorphic to those with mod 4. We
describe the fully nonlinear higher spin theories based on these algebras as
well, and we elaborate further on the supersymmetric theory,
providing two equivalent descriptions one of which exhibits manifestly its
relation to the supersymmetric higher spin theory.Comment: 30 pages. Contribution to J. Phys. A special volume on "Higher Spin
Theories and AdS/CFT" edited by M. R. Gaberdiel and M. Vasilie
Hamiltonian analysis of Poincar\'e gauge theory scalar modes
The Hamiltonian constraint formalism is used to obtain the first explicit
complete analysis of non-trivial viable dynamic modes for the Poincar\'e gauge
theory of gravity. Two modes with propagating spin-zero torsion are analyzed.
The explicit form of the Hamiltonian is presented. All constraints are obtained
and classified. The Lagrange multipliers are derived. It is shown that a
massive spin- mode has normal dynamical propagation but the associated
massless is pure gauge. The spin- mode investigated here is also
viable in general. Both modes exhibit a simple type of ``constraint
bifurcation'' for certain special field/parameter values.Comment: 28 pages, LaTex, submitted to International Journal of Modern Physics
A note on positive energy of topologically massive gravity
I review how "classical SUGRA" embeddability establishes positive energy E
for D=3 topologically massive gravity (TMG), with or without a cosmological
term, a procedure familiar from D=4 Einstein gravity (GR). It also provides
explicit expressions for E. In contrast to GR, E is not manifestly positive,
due to the peculiar two-term nature of TMG.Comment: 7 page
Kundt spacetimes as solutions of topologically massive gravity
We obtain new solutions of topologically massive gravity. We find the general
Kundt solutions, which in three dimensions are spacetimes admitting an
expansion-free null geodesic congruence. The solutions are generically of
algebraic type II, but special cases are types III, N or D. Those of type D are
the known spacelike-squashed AdS_3 solutions, and of type N are the known AdS
pp-waves or new solutions. Those of types II and III are the first known
solutions of these algebraic types. We present explicitly the Kundt solutions
that are CSI spacetimes, for which all scalar polynomial curvature invariants
are constant, whereas for the general case we reduce the field equations to a
series of ordinary differential equations. The CSI solutions of types II and
III are deformations of spacelike-squashed AdS_3 and the round AdS_3,
respectively.Comment: 30 pages. This material has come from splitting v1 of arXiv:0906.3559
into 2 separate papers. v2: minor changes
Test particles behavior in the framework of a lagrangian geometric theory with propagating torsion
Working in the lagrangian framework, we develop a geometric theory in vacuum
with propagating torsion; the antisymmetric and trace parts of the torsion
tensor, considered as derived from local potential fields, are taken and, using
the minimal action principle, their field equations are calculated. Actually
these will show themselves to be just equations for propagating waves giving
torsion a behavior similar to that of metric which, as known, propagates
through gravitational waves. Then we establish a principle of minimal
substitution to derive test particles equation of motion, obtaining, as result,
that they move along autoparallels. We then calculate the analogous of the
geodesic deviation for these trajectories and analyze their behavior in the
nonrelativistic limit, showing that the torsion trace potential has a
phenomenology which is indistinguishable from that of the gravitational
newtonian field; in this way we also give a reason for why there have never
been evidence for it.Comment: 12 pages, no figures, to appear on Int. Journ. Mod. Phys.
An action principle for Vasiliev's four-dimensional higher-spin gravity
We provide Vasiliev's fully nonlinear equations of motion for bosonic gauge
fields in four spacetime dimensions with an action principle. We first extend
Vasiliev's original system with differential forms in degrees higher than one.
We then derive the resulting duality-extended equations of motion from a
variational principle based on a generalized Hamiltonian sigma-model action.
The generalized Hamiltonian contains two types of interaction freedoms: One set
of functions that appears in the Q-structure of the generalized curvatures of
the odd forms in the duality-extended system; and another set depending on the
Lagrange multipliers, encoding a generalized Poisson structure, i.e. a set of
polyvector fields of ranks two or higher in target space. We find that at least
one of the two sets of interaction-freedom functions must be linear in order to
ensure gauge invariance. We discuss consistent truncations to the minimal Type
A and B models (with only even spins), spectral flows on-shell and provide
boundary conditions on fields and gauge parameters that are compatible with the
variational principle and that make the duality-extended system equivalent, on
shell, to Vasiliev's original system.Comment: 37 pages. References added, corrected typo
Noncompact gaugings, chiral reduction and dual sigma models in supergravity
We show that the half-maximal SU(2) gauged supergravity with topological mass
term admits coupling of an arbitrary number of n vector multiplets. The chiral
circle reduction of the ungauged theory in the dual 2-form formulation gives
N=(1,0) supergravity in 6D coupled to 3p scalars that parametrize the coset
SO(p,3)/SO(p)x SO(3), a dilaton and (p+3) axions with p < n+1. Demanding that
R-symmetry gauging survives in 6D is shown to put severe restrictions on the 7D
model, in particular requiring noncompact gaugings. We find that the SO(2,2)
and SO(3,1) gauged 7D supergravities give a U(1)_R, and the SO(2,1) gauged 7D
supergravity gives an Sp(1)_R gauged chiral 6D supergravities coupled to
certain matter multiplets. In the 6D models obtained, with or without gauging,
we show that the scalar fields of the matter sector parametrize the coset
SO(p+1,4)/SO(p+1)x SO(4), with the (p+3) axions corresponding to its abelian
isometries. In the ungauged 6D models, upon dualizing the axions to 4-form
potentials, we obtain coupling of p linear multiplets and one special linear
multiplet to chiral 6D supergravity.Comment: 41 pages, late
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