296 research outputs found
Killing Spinor Equations from Nonlinear Realisations
Starting from a nonlinear realisation of eleven dimensional supergravity
based on the group G11, whose generators appear as low level generators of E11,
we present a super extended algebra, which leads to a covariant derivative of
spinors identical to the Killing spinor equation of this theory. A similar
construction leads to the Killing spinor equation of N=1 pure supergravity in
ten dimensions.Comment: 16 pages, typos correcte
IIA and IIB spinors from K(E10)
We analyze the decomposition of recently constructed unfaithful spinor
representations of K(E10) under its SO(9) x SO(9), and SO(9) x SO(2) subgroups,
respectively, where K(E10) is the `maximal compact' subgroup of the hyperbolic
Kac--Moody group E(10). We show that under these decompositions, respectively,
one and the same K(E10) spinor gives rise to both the fermionic fields of IIA
supergravity, and to the (chiral) fermionic fields of IIB supergravity. This
result is thus the fermionic analogue of the decomposition of E(10) under its
SO(9,9) and SL(9) x SL(2) subgroups, respectively, which yield the correct
bosonic multiplets of (massive) IIA and IIB supergravity. The essentially
unique Lagrangian for the supersymmetric E(10)/K(E10) sigma-model therefore can
also capture the dynamics of IIA and IIB including bosons and fermions in the
known truncations.Comment: 16 pages, v2: added paragraph on spinors for K(E9) and K(E11
Kac-Moody Symmetries of Ten-dimensional Non-maximal Supergravity Theories
A description of the bosonic sector of ten-dimensional N=1 supergravity as a
non-linear realisation is given. We show that if a suitable extension of this
theory were invariant under a Kac-Moody algebra, then this algebra would have
to contain a rank eleven Kac-Moody algebra, that can be identified to be a
particular real form of very-extended D_8. We also describe the extension of
N=1 supergravity coupled to an abelian vector gauge field as a non-linear
realisation, and find the Kac-Moody algebra governing the symmetries of this
theory to be very-extended B_8. Finally, we discuss the related points for the
N=1 supergravity coupled to an arbitrary number of abelian vector gauge fields
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
Hidden symmetries and the fermionic sector of eleven-dimensional supergravity
We study the hidden symmetries of the fermionic sector of D=11 supergravity,
and the role of K(E10) as a generalised `R-symmetry'. We find a consistent
model of a massless spinning particle on an E10/K(E10) coset manifold whose
dynamics can be mapped onto the fermionic and bosonic dynamics of D=11
supergravity in the near space-like singularity limit. This E10-invariant
superparticle dynamics might provide the basis of a new definition of M-theory,
and might describe the `de-emergence' of space-time near a cosmological
singularity.Comment: 15 pages, v2: updated references and typos corrected, v3: updated
references and minor correction
Pregna-1,4,20-trien-3-one, a cytotoxic marine steroid from the marine soft coral Nephthea sp.
The title compound, C21H28O, was isolated from the cytotoxic lipid extract of the Fidjian soft coral Nephthea sp. The steroid showed inhibitory activity to human colon adenocarcinoma SW480 cells (IC50 = 2.5 µg ml−1). The molecular structure indicates that the A ring is almost planar (r.m.s. deviation = 0.032 Å), the B and C rings adopt chair conformations and the five-membered D ring is a half-chair. The B/C and C/D ring junctions are trans-fused
Kac-Moody Symmetries of IIB Supergravity
We formulate the bosonic sector of IIB supergravity as a non-linear
realisation. We show that this non-linear realisation contains the Borel
subalgebras of SL(11) and and argue that it can be enlarged so as to be
based on the rank eleven Kac-Moody algebra Comment: 12 pages, plain te
E11 and Spheric Vacuum Solutions of Eleven- and Ten dimensional Supergravity Theories
In view of the newly conjectured Kac-Moody symmetries of supergravity
theories placed in eleven and ten dimensions, the relation between these
symmetry groups and possible compactifications are examined. In particular, we
identify the relevant group cosets that parametrise the vacuum solutions of AdS
x S type.Comment: discussion improve
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