486 research outputs found
Generalised BPS conditions
We write down two E11 invariant conditions which at low levels reproduce the
known half BPS conditions for type II theories. These new conditions contain,
in addition to the familiar central charges, an infinite number of further
charges which are required in an underlying theory of strings and branes. We
comment on the application of this work to higher derivative string
corrections
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
A Note on E11 and Three-dimensional Gauged Supergravity
We determine the gauge symmetries of all p-forms in maximal three-dimensional
gauged supergravity by requiring invariance of the Lagrangian. It is shown that
in a particular ungauged limit these symmetries are in precise correspondence
to those predicted by the very-extended Kac-Moody algebra E11. We demonstrate
that whereas in the ungauged limit the bosonic gauge algebra closes off-shell,
the closure is only on-shell in the full gauged theory. This underlines the
importance of dynamics for understanding the Kac-Moody origin of the symmetries
of gauged supergravity.Comment: Published versio
Generalised geometry, eleven dimensions and E11
We construct the non-linear realisation of E11 and its first fundamental
representation in eleven dimensions at low levels. The fields depend on the
usual coordinates of space-time as well as two form and five form coordinates.
We derive the terms in the dynamics that contain the three form and six form
fields and show that when we restricted their field dependence to be only on
the usual space-time we recover the correct self-duality relation. Should this
result generalise to the gravity fields then the non-linear realisation is an
extension of the maximal supergravity theory, as previously conjectured. We
also comment on the connections between the different approaches to generalised
geometry.Comment: 17 pages, Trivial typos corrected in version one and a substantial
note added which gives the equation of motion relating the gravity field to
its dua
Tensor hierarchies, Borcherds algebras and E11
Gauge deformations of maximal supergravity in D=11-n dimensions generically
give rise to a tensor hierarchy of p-form fields that transform in specific
representations of the global symmetry group E(n). We derive the formulas
defining the hierarchy from a Borcherds superalgebra corresponding to E(n).
This explains why the E(n) representations in the tensor hierarchies also
appear in the level decomposition of the Borcherds superalgebra. We show that
the indefinite Kac-Moody algebra E(11) can be used equivalently to determine
these representations, up to p=D, and for arbitrarily large p if E(11) is
replaced by E(r) with sufficiently large rank r.Comment: 22 pages. v2: Published version (except for a few minor typos
detected after the proofreading, which are now corrected
Non-geometric fluxes and mixed-symmetry potentials
We discuss the relation between generalised fluxes and mixed-symmetry
potentials. We first consider the NS fluxes, and point out that the
`non-geometric' flux is dual to a mixed-symmetry potential with a set of
nine antisymmetric indices. We then consider the T-duality family of fluxes
whose prototype is the Scherk-Schwarz reduction of the S-dual of the RR scalar
of IIB supergravity. Using the relation with mixed-symmetry potentials, we are
able to give a complete classification of these fluxes, including the ones that
are non-geometric. The non-geometric fluxes again turn out to be dual to
potentials containing nine antisymmetric indices. Our analysis suggests that
all these fluxes can be understood in the context of double field theory,
although for the non-geometric ones one expects a violation of the strong
constraint.Comment: 19 pages, refs. adde
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
Non-propagating degrees of freedom in supergravity and very extended G_2
Recently a correspondence between non-propagating degrees of freedom in
maximal supergravity and the very extended algebra E_11 has been found. We
perform a similar analysis for a supergravity theory with eight supercharges
and very extended G_2. In particular, in the context of d=5 minimal
supergravity, we study whether supersymmetry can be realised on higher-rank
tensors with no propagating degrees of freedom. We find that in this case the
very extended algebra fails to capture these possibilities.Comment: 12 pages, 1 figure. v2: transformation properties of higher-rank
tensors under SU(2) R-symmetry analysed and refs added. v3: improved
discussion, published versio
The different faces of branes in Double Field Theory
We show how the Wess-Zumino terms of the different branes in string theory can be embedded within double field theory. Crucial ingredients in our construction are the identification of the correct brane charge tensors {and the use of the} double field theory potentials that arise from dualizing the standard double field theory fields. This leads to a picture where under T-duality the brane does not change its worldvolume directions but where, instead, it shows different faces depending on whether some of the worldvolume and/or transverse directions invade the winding space. As a non-trivial by-product we show how the different Wess-Zumino terms are modified when the brane propagates in a background with a non-zero Romans mass parameter. Furthermore, we show that for non-zero mass parameter the brane creation process, when one brane passes through another brane, gets generalized to brane configurations that involve exotic branes as well
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