73 research outputs found
Duality Symmetries and G^{+++} Theories
We show that the non-linear realisations of all the very extended algebras
G^{+++}, except the B and C series which we do not consider, contain fields
corresponding to all possible duality symmetries of the on-shell degrees of
freedom of these theories. This result also holds for G_2^{+++} and we argue
that the non-linear realisation of this algebra accounts precisely for the form
fields present in the corresponding supersymmetric theory. We also find a
simple necessary condition for the roots to belong to a G^{+++} algebra.Comment: 35 pages. v2: 2 appendices added, other minor corrections. v3: tables
corrected, other minor changes, one appendix added, refs. added. Version
published in Class. Quant. Gra
Diagrammar and metamorphosis of coset symmetries in dimensionally reduced type IIB supergravity
Studying the reduction of type IIB supergravity from ten to three space-time
dimensions we describe the metamorphosis of Dynkin diagram for gravity line
"caterpillar" into a type IIB supergravity "dragonfly" that is triggered by
inclusion of scalars and antisymmetric tensor fields. The final diagram
corresponds to type IIB string theory E8 global symmetry group which is the
subgroup of the conjectured E11 hidden symmetry group. Application of the
results for getting the type IIA/IIB T-duality rules and for searching for type
IIB vacua solutions is considered.Comment: 9 pp, 7 figs, LATEX; to be published in JETP Let
IIA/IIB Supergravity and Ten-forms
We perform a careful investigation of which p-form fields can be introduced
consistently with the supersymmetry algebra of IIA and/or IIB ten-dimensional
supergravity. In particular the ten-forms, also known as "top-forms", require a
careful analysis since in this case, as we will show, closure of the
supersymmetry algebra at the linear level does not imply closure at the
non-linear level. Consequently, some of the (IIA and IIB) ten-form potentials
introduced in earlier work of some of us are discarded. At the same time we
show that new ten-form potentials, consistent with the full non-linear
supersymmetry algebra can be introduced. We give a superspace explanation of
our work. All of our results are precisely in line with the predictions of the
E(11) algebra.Comment: 17 page
Generalised Space-time and Gauge Transformations
We consider the generalised space-time introduced by the author in 2003 in
the context of the non-linear realisation of the semi-direct product of E11 and
its first fundamental representation. For all the fields we propose gauge
transformations which are compatible with the underlying E11 structure. A
crucial role is played by the generalised vielbein that the generalised
space-time possess. We work out the explicit form of the gauge transformations,
at low levels, in four, five and eleven dimensions.Comment: 33 page
D-Brane Wess-Zumino Terms and U-Duality
We construct gauge-invariant and U-duality covariant expressions for
Wess-Zumino terms corresponding to general Dp-branes (for any p<D) in arbitrary
2<D<11 dimensions. A distinguishing feature of these Wess-Zumino terms is that
they contain twice as many scalars as the 10-D compactified dimensions, in line
with doubled geometry. We find that for D<10 the charges of the
higher-dimensional branes can all be expressed as products of the 0-brane
charges, which include the D0-brane and the NS-NS 0-brane charges. We give the
general expressions for these charges and show how they determine the
non-trivial conjugacy class to which some of the higher-dimensional D-branes
belong.Comment: 42 pages. Typos corrected, an error in table 6 corrected, comments in
the conclusions adde
Hidden Symmetries and Dirac Fermions
In this paper, two things are done. First, we analyze the compatibility of
Dirac fermions with the hidden duality symmetries which appear in the toroidal
compactification of gravitational theories down to three spacetime dimensions.
We show that the Pauli couplings to the p-forms can be adjusted, for all simple
(split) groups, so that the fermions transform in a representation of the
maximal compact subgroup of the duality group G in three dimensions. Second, we
investigate how the Dirac fermions fit in the conjectured hidden overextended
symmetry G++. We show compatibility with this symmetry up to the same level as
in the pure bosonic case. We also investigate the BKL behaviour of the
Einstein-Dirac-p-form systems and provide a group theoretical interpretation of
the Belinskii-Khalatnikov result that the Dirac field removes chaos.Comment: 30 page
Holography in asymptotically flat space-times and the BMS group
In a previous paper (hep-th/0306142) we have started to explore the
holographic principle in the case of asymptotically flat space-times and
analyzed in particular different aspects of the Bondi-Metzner-Sachs (BMS)
group, namely the asymptotic symmetry group of any asymptotically flat
space-time. We continue this investigation in this paper. Having in mind a
S-matrix approach with future and past null infinity playing the role of
holographic screens on which the BMS group acts, we connect the IR sectors of
the gravitational field with the representation theory of the BMS group. We
analyze the (complicated) mapping between bulk and boundary symmetries pointing
out differences with respect to the AdS/CFT set up. Finally we construct a BMS
phase space and a free hamiltonian for fields transforming w.r.t BMS
representations. The last step is supposed to be an explorative investigation
of the boundary data living on the degenerate null manifold at infinity.Comment: 31 pages, several changes in section 3 and 7 and references update
Kac-Moody Spectrum of (Half-)Maximal Supergravities
We establish the correspondence between, on one side, the possible gaugings
and massive deformations of half-maximal supergravity coupled to vector
multiplets and, on the other side, certain generators of the associated very
extended Kac-Moody algebras. The difference between generators associated to
gaugings and to massive deformations is pointed out. Furthermore, we argue that
another set of generators are related to the so-called quadratic constraints of
the embedding tensor. Special emphasis is placed on a truncation of the
Kac-Moody algebra that is related to the bosonic gauge transformations of
supergravity. We give a separate discussion of this truncation when non-zero
deformations are present. The new insights are also illustrated in the context
of maximal supergravity.Comment: Added references, published versio
Primary hyperoxaluria Type 1: indications for screening and guidance for diagnosis and treatment
Black brane solutions related to non-singular Kac-Moody algebras
A multidimensional gravitational model containing scalar fields and
antisymmetric forms is considered. The manifold is chosen in the form M = M_0 x
M_1 x ... x M_n, where M_i are Einstein spaces (i > 0). The sigma-model
approach and exact solutions with intersecting composite branes (e.g.,
solutions with harmonic functions and black brane ones) with intersection rules
related to non-singular Kac-Moody (KM) algebras (e.g. hyperbolic ones) are
considered. Some examples of black brane solutions are presented, e.g., those
corresponding to hyperbolic KM algebras: H_2(q,q) (q > 2), HA_2^(1) = A_2^{++}
and to the Lorentzian KM algebra P_{10}.Comment: 16 pages, Late
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