1,582 research outputs found
p-Branes, D-Branes and M-Branes
We consider solutions to the string effective action corresponding to
p-Branes, D-Branes and M-Branes and discuss some of their properties.Comment: 8 pages, latex, uses sprocl.sty; talk given at the Workshop on Gauge
Theories, Applied Supersymmetry and Quantum Gravity (London, July 1996) and
the Strings '96 conference, ``Current Trends in String Theory'' (Santa
Barbara, July 1996
Super D-branes
We present a manifestly Lorentz invariant, spacetime supersymmetric, and
`-invariant' worldvolume action for all type II Dirichlet p-branes,
, in a general type II supergravity background, including massive
backgrounds in the IIA case. The cases are rederived from D=11. The
case provides a supersymmetrization of the D=10 Born-Infeld action.Comment: 27pp. Typos corrected. To appear in Nucl. Phys.
Solitons on the Supermembrane
Energy bounds are derived for planar and compactified M2-branes in a
hyper-K\"ahler background. These bounds are saturated, respectively, by lump
and Q-kink solitons, which are shown to preserve a half of the worldvolume
supersymmetry. The Q-kinks have a dual IIB interpretation as strings that
migrate between fivebranes.Comment: 18 pp. Latex; v2: minor corrections, version as published in JHE
Some interesting features of new massive gravity
A proof that new massive gravity - the massive 3D gravity model proposed by
Bergshoeff, Hohm and Townsend (BHT) - is the only unitary system at the tree
level that can be constructed by augmenting planar gravity through the
curvature-squared terms, is presented. Two interesting gravitational properties
of the BHT model, namely, time dilation and time delay, which have no
counterpart in the usual Einstein 3D gravity, are analyzed as well.Comment: Submitted to Classical and Quantum Gravit
Stationary Axion/Dilaton Solutions and Supersymmetry
We present a new set of supersymmetric stationary solutions of pure N=4,d=4
supergravity (and, hence, of low-energy effective string theory) that
generalize (and include) the Israel-Wilson-Perj\'es solutions of
Einstein-Maxwell theory. All solutions have 1/4 of the supersymmetries unbroken
and some have 1/2. The full solution is determined by two arbitrary complex
harmonic functions {\cal H}_{1,2} which transform as a doublet under SL(2,\R) S
duality and N complex constants k^{(n)} that transform as an SO(N) vector. This
set of solutions is, then, manifestly duality invariant. When the harmonic
functions are chosen to have only one pole, all the general resulting
point-like objects have supersymmetric rotating asymptotically Taub-NUT metrics
with 1/2 or 1/4 of the supersymmetries unbroken. The static, asymptotically
flat metrics describe supersymmetric extreme black holes. Only those breaking
3/4 of the supersymmetries have regular horizons. The stationary asymptotically
flat metrics do not describe black holes when the angular momentum does not
vanish, even in the case in which 3/4 of the supersymmetries are broken.Comment: A few comments added and alternative formulae for the horizon area
with manifest moduli-independence and duality-invariance given. 36 page
Realisations of Symmetry
We perform a systematic investigation of free-scalar realisations of the
Za\-mo\-lod\-chi\-kov algebra in which the operator product of two
spin-three generators contains a non-zero operator of spin four which has
vanishing norm. This generalises earlier work where such an operator was
required to be absent. By allowing this spin-four null operator we obtain
several realisations of the algebra both in terms of two scalars as well
as in terms of an arbitrary number of free scalars. Our analysis is
complete for the case of two-scalar realisations.Comment: 14 pages, LATEX, UG-6/9
Hypermultiplets and hypercomplex geometry from 6 to 3 dimensions
The formulation of hypermultiplets that has been developed for 5-dimensional
matter multiplets is by dimensional reductions translated into the appropriate
spinor language for 6 and 4 dimensions. We also treat the theories without
actions that have the geometrical structure of hypercomplex geometry. The
latter is the generalization of hyper-Kaehler geometry that does not require a
Hermitian metric and hence corresponds to field equations without action. The
translation tables of this paper allow the direct application of superconformal
tensor calculus for the hypermultiplets using the available Weyl multiplets in
6 and 4 dimensions. Furthermore, the hypermultiplets in 3 dimensions that
result from reduction of vector multiplets in 4 dimensions are considered,
leading to a superconformal formulation of the c-map and an expression for the
main geometric quantities of the hyper-Kaehler manifolds in the image of this
map.Comment: 18 pages; v2: several clarifications in text and formulae, version to
appear in Class.Quantum Gravit
Massive Dualities in Six Dimensions
We study compactifications of string theory and M-theory to six dimensions
with background fluxes. The nonzero fluxes lead to additional mass parameters.
We derive the S- and T-duality rules for the corresponding (massive)
supergravity theories. Specifically, we investigate the massive T-duality
between Type IIA superstring theory compactified on K3 with background fluxes
and Type IIB superstring theory compactified on K3. Furthermore, we generalise
to the massive case the 6D 'string-string' S-duality between M-theory on K3 x
S^1 and the Heterotic String on T^4. Whereas in the case of massive T--duality
the mass parameters are in the fundamental representation of the U-duality
group O(4,20) we find that in the case of massive S-duality they are in the
3-index antisymmetric representation. In the latter case the mass parameters
involved extend those of Kaloper and Myers. We apply our duality rules to
massive brane solutions, like the domain wall solutions corresponding to the
mass parameters and find new massive brane solutions. Finally, we discuss the
higher-dimensional interpretation of the dualities and brane solutions.Comment: 28 page
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