3,500 research outputs found
University of Arkansas at Monticello\u27s 1985 Summer Science Institute: A Report and an Opinion
The University of Arkansas at Monticello\u27s 1985 Summer Science Institute was created to improve competence in science among on-the-job upper elementary school teachers (grades 4-6) in southeast Arkansas. Students received three weeks of solid introductory coursework in botany, chemistry, and geology. However, deficiencies in public school science education are extensive and deeply rooted and will not be seriously addressed by anything less than radical changes in teacher training and certification policies
Rezension zu: Fritz Graf – Sarah Iles Johnston, Ritual texts for the afterlife. Orpheus and the Bacchic gold tablets (2007)
A Fiber Approach to Harmonic Analysis of Unfolded Higher-Spin Field Equations
In Vasiliev's unfolded formulation of higher-spin dynamics the standard
fields are embedded on-shell into covariantly constant master fields valued in
Lorentz-covariant slices of the star-product algebra A of functions on the
singleton phase space. Correspondingly, the harmonic expansion is taken over
compact slices of A that are unitarizable in a rescaled trace-norm rather than
the standard Killing norm. Motivated by the higher-derivative nature of the
theory, we examine indecomposable unitarizable Harish-Chandra modules
consisting of standard massless particles plus linearized runaway solutions.
This extension arises naturally in the above fiber approach upon realizing
compact-weight states as non-polynomial analytic functions in A.Comment: 80 pages, 2 figures. Minor changes: typos corrected, two footnotes
and references added. To be published in JHE
4D Higher Spin Black Holes with Nonlinear Scalar Fluctuations
We construct an infinite-dimensional space of solutions to Vasiliev's
equations in four dimensions that are asymptotic to AdS spacetime and superpose
massless scalar particle modes over static higher spin black holes. Each
solution is obtained by a large gauge transformation of an all-order
perturbatively defined particular solution given in a simple gauge, in which
the spacetime connection vanishes, the twistor space connection is holomorphic,
and all local degrees of freedom are encoded into the residual twistor space
dependence of the spacetime zero-forms. The latter are expanded over two dual
spaces of Fock space operators, corresponding to scalar particle and static
black hole modes, equipped with positive definite sesquilinear and bilinear
forms, respectively. Switching on an AdS vacuum gauge function, the twistor
space connection becomes analytic at generic spacetime points, which makes it
possible to reach Vasiliev's gauge, in which Fronsdal fields arise
asymptotically, by another large transformation given here at first order. The
particle and black hole modes are related by a twistor space Fourier transform,
resulting in a black hole backreaction already at the second order of classical
perturbation theory. We speculate on the existence of a fine-tuned branch of
moduli space that is free from black hole modes and directly related to the
quasi-local deformed Fronsdal theory. Finally, we comment on a possible
interpretation of the higher spin black hole solutions as black-hole
microstates.Comment: 63 pages + appendices; v2: reference added; v3: comments and
references added, typos correcte
Open String/Open D-Brane Dualities: Old and New
We examine magnetic and electric near horizon regions of maximally
supersymmetric D-brane and NS5-brane bound states and find transformations
between near horizon regions with worldvolume dual magnetic and electric
fluxes. These point to dual formulations of NCYM, NCOS and OD theories in
the limit of weak coupling and large spatial or temporal non-commutativity
length scale in terms of weakly coupled theories with fixed worldvolume dual
non-commutativity based on open D-branes. We also examine the strong coupling
behavior of the open D-brane theories and propose a unified web of dualities
involving strong/weak coupling as well as large/small non-commutativity scale.Comment: 33 pages, Latex, 8 diagrams, added references and a remar
Higher Spin N=8 Supergravity
The product of two N=8 supersingletons yields an infinite tower of massless
states of higher spin in four dimensional anti de Sitter space. All the states
with spin s > 1/2 correspond to generators of Vasiliev's super higher spin
algebra shs^E (8|4) which contains the D=4, N=8 anti de Sitter superalgebra
OSp(8|4). Gauging the higher spin algebra and introducing a matter multiplet in
a quasi-adjoint representation leads to a consistent and fully nonlinear
equations of motion as shown sometime ago by Vasiliev. We show the embedding of
the N=8 AdS supergravity equations of motion in the full system at the
linearized level and discuss the implications for the embedding of the
interacting theory. We furthermore speculate that the boundary N=8 singleton
field theory yields the dynamics of the N=8 AdS supergravity in the bulk,
including all higher spin massless fields, in an unbroken phase of M-theory.Comment: 64 pages, latex, considerably expanded version, submitted for
publicatio
Towards Massless Higher Spin Extension of D=5, N=8 Gauged Supergravity
The AdS_5 superalgebra PSU(2,2|4) has an infinite dimensional extension,
which we denote by hs(2,2|4). We show that the gauging of hs(2,2|4) gives rise
to a spectrum of physical massless fields which coincides with the symmetric
tensor product of two AdS_5 spin-1 doubletons (i.e. the N=4 SYM multiplets
living on the boundary of AdS_5). This product decomposes into levels
\ell=0,1,2,..,\infty of massless supermultiplets of PSU(2,2|4). In particular,
the D=5, N=8 supergravity multiplet arises at level \ell=0. In addition to a
master gauge field, we construct a master scalar field containing the s=0,1/2
fields, the anti-symmetric tensor field of the gauged supergravity and its
higher spin analogs. We define the linearized constraints and obtain the
linearized field equations of the full spectrum, including those of D=5,N=8
gauged supergravity and in particular the self-duality equations for the 2-form
potentials of the gauged supergravity (forming a 6-plet of SU(4)), and their
higher spin cousins with s=2,3,...,\infty.Comment: 36 pages, late
Higher Spin Gravity Amplitudes From Zero-form Charges
We examine zero-form charges in Vasiliev's four-dimensional bosonic higher
spin gravities. These are classical observables given by integrals over
noncommutative twistor space of adjoint combinations of the zero-form master
fields, including insertions of delta functions in the deformed oscillators
serving as gauge invariant regulators. The regularized charges admit
perturbative expansions in terms of multi-linear functionals in the Weyl
zero-form, which are Bose symmetric and higher spin invariant by construction,
and that can be interpreted as basic building blocks for higher spin gravity
amplitudes. We compute two- and three-point functions by attaching external
legs given by unfolded bulk-to-boundary propagators, and identify the result
with the two- and three-current correlation functions in theories of free
conformal scalars and fermions in three dimensions. Modulo assumptions on the
structure of the sub-leading corrections, and relying on the generalized
Hamiltonian off-shell formulation, we are thus led to propose an expression for
the free energy as a sum of suitably normalized zero-form chargesComment: V2: Typos corrected, references added, footnote and note added,
discussion section improve
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