279,150 research outputs found
Dualisation of the Salam-Sezgin D=8 Supergravity
The first-order formulation of the Salam-Sezgin D=8 supergravity coupled to N
vector multiplets is discussed. The non-linear realization of the bosonic
sector of the D=8 matter coupled Salam-Sezgin supergravity is introduced by the
dualisation of the fields and by constructing the Lie superalgebra of the
symmetry group of the doubled field strength.Comment: 15 page
Self-Duality in D <= 8-dimensional Euclidean Gravity
In the context of D-dimensional Euclidean gravity, we define the natural
generalisation to D-dimensions of the self-dual Yang-Mills equations, as
duality conditions on the curvature 2-form of a Riemannian manifold. Solutions
to these self-duality equations are provided by manifolds of SU(2), SU(3), G_2
and Spin(7) holonomy. The equations in eight dimensions are a master set for
those in lower dimensions. By considering gauge fields propagating on these
self-dual manifolds and embedding the spin connection in the gauge connection,
solutions to the D-dimensional equations for self-dual Yang-Mills fields are
found. We show that the Yang-Mills action on such manifolds is topologically
bounded from below, with the bound saturated precisely when the Yang-Mills
field is self-dual. These results have a natural interpretation in
supersymmetric string theory.Comment: 9 pages, Latex, factors in eqn. (6) corrected, acknowledgement and
reference added, typos fixe
On Heterotic/Type I Duality in d=8
We discuss heterotic corrections to quartic internal U(1) gauge couplings and
check duality by calculating one-loop open string diagrams and identifying the
D-instanton sum in the dual type I picture. We also compute SO(8)^4 threshold
corrections and finally R^2 corrections in type I theory.Comment: 9 pages, Latex, To appear in the proceedings of "Quantum Aspects of
Gauge Theories, Supersymmetries and Unification", Corfu, September 199
A classification of local Weyl invariants in D=8
Following a purely algebraic procedure, we provide an exhaustive
classification of local Weyl-invariant scalar densities in dimension D=8.Comment: LaTeX, 19 pages, typos corrected, one reference adde
Ligand design for site-selective installation of Pd and Pt centers to generate homo- and heteropolymetallic motifs
The modular synthesis of a series of nitrogen-rich polydentate ligands that feature a common pincer-type framework is reported. These ligands allow for site-selective installation of palladium and platinum to give rise to bi- and trimetallic complexes that have d^(8)–d^(8) interactions
The Spacetime Superalgebras in a Massive IIA Background via Brane Probes
We derive the spacetime superalgebras explicitly from ``test'' p-brane
actions in a D-8-brane (i.e. a massive IIA) background to the lowest order in
via canonical formalism, and show that the forms of the superalgebras
are the same as those in all the other D-brane (i.e. massless IIA) backgrounds,
that is, they are indifferent to the presence of the Chern-Simons terms which
are proportional to the mass and added to the D-brane actions in the case of
massive IIA backgrounds. Thus, we can say that all the D-brane background
solutions including a D-8-brane are on equal footing from the viewpoint of the
superalgebras via brane probes. We also deduce from the algebra all the
previously known 1/4 supersymmetric intersections of a p-brane or a fundamental
string with a D-8-brane, as the supersymmetric ``gauge fixings'' of the test
branes in the D-8-brane background.Comment: 15pages, Latex, in v2 two references added and some grammatical and
spelling errors corrected. in v3 the title is a bit modified and one
reference is adde
Is the droplet theory for the Ising spin glass inconsistent with replica field theory?
Symmetry arguments are used to derive a set of exact identities between
irreducible vertex functions for the replica symmetric field theory of the
Ising spin glass in zero magnetic field. Their range of applicability spans
from mean field to short ranged systems in physical dimensions. The replica
symmetric theory is unstable for d>8, just like in mean field theory. For 6<d<8
and d<6 the resummation of an infinite number of terms is necessary to settle
the problem. When d<8, these Ward-like identities must be used to distinguish
an Almeida-Thouless line from the replica symmetric droplet phase.Comment: 4 pages. Accepted for publication in J.Phys.A. This is the accepted
version with the following minor changes: one extra sentence in the abstract;
footnote 2 slightly extended; last paragraph somewhat reformulate
Counterterms in type I Supergravities
We compute the one-loop divergences of D=10, N=1 supergravity and of its
reduction to D=8. We study the tensor structure of the counterterms appearing
in D=8 and D=10 and compare these to expressions previously found in the low
energy expansion of string theory. The infinities have the primitive Yang-Mills
tree amplitude as a common factor.Comment: 26 pages, Latex, 4 eps figure
- …