380 research outputs found
Bent BPS domain walls of D=5 N=2 gauged supergravity coupled to hypermultiplets
Within D=5 N=2 gauged supergravity coupled to hypermultiplets we derive
consistency conditions for BPS domain walls with constant negative curvature on
the wall. For such wall solutions to exist, the covariant derivative of the
projector, governing the constraint on the Killing spinor, has to be non-zero
and proportional to the cosmological constant on the domain walls. We also
prove that in this case solutions of the Killing spinor equations are solutions
of the equations of motion. We present explicit, analytically solved examples
of such domain walls, employing the universal hypermultiplet fields. These
examples involve the running of two scalar fields and the space-time in the
transverse direction that is cut off at a critical distance, governed by the
magnitude of the negative cosmological constant on the wall.Comment: 18 pages, Late
Superpotentials from flux compactifications of M-theory
In flux compactifications of M-theory a superpotential is generated whose
explicit form depends on the structure group of the 7-dimensional internal
manifold. In this note, we discuss superpotentials for the structure groups:
G_2, SU(3) or SU(2). For the G_2 case all internal fluxes have to vanish. For
SU(3) structures, the non-zero flux components entering the superpotential
describe an effective 1-dimensional model and a Chern-Simons model if there are
SU(2) structures.Comment: 10 page
Time-dependent backgrounds from supergravity with gauged non-compact R-symmetry
We obtain a general class of time-dependent, asymptotically de Sitter
backgrounds which solve the first order bosonic equations that extremize the
action for supergravity with gauged non-compact -symmetry. These backgrounds
correspond only to neutral fields with the correct sign of kinetic energy.
Within N=2 five-dimensional supergravity with vector-superfields we provide
examples of multi-centered charged black holes in asymptotic de Sitter space,
whose spatial part is given by a time-dependent hyper-K\"ahler space. Reducing
these backgrounds to four dimensions yields asymptotically de Sitter
multi-centered charged black hole backgrounds and we show that they are related
to an instanton configuration by a massive T-duality over time. Within N=2
gauged supergravity in four (and five)-dimensions with hyper-multiplets there
could also be neutral cosmological backgrounds that are regular and correspond
to the different de Sitter spaces at early and late times.Comment: 28 pages, Latex; minor changes and add reference
BPS-Saturated Bound States of Tilted P-Branes in Type II String Theory
We found BPS-saturated solutions of M-theory and Type II string theory which
correspond to (non-marginally) bound states of p-branes intersecting at angles
different from pi/2. These solutions are obtained by starting with a BPS
marginally bound (orthogonally) intersecting configurations of two p-branes
(e.g, two four-branes of Type II string theory), performing a boost
transformation at an angle with respect to the world-volume of the
configuration, performing T-duality transformation along the boost-direction,
S-duality transformation, and T- transformations along the direction
perpendicular to the boost transformation. The resulting configuration is
non-marginally bound BPS-saturated solution whose static metric possesses the
off-diagonal term which cannot be removed by a coordinate transformation, and
thus signifies an angle (different from pi/2) between the resulting
intersecting p-branes. Additional new p-branes are bound to this configuration,
in order to ensure the stability of such a static, tilted configuration.Comment: 11 pages, Latex with two postscript figures, minor corrections,
version to appear in Phys. Rev.
Curved BPS domain walls and RG flow in five dimensions
We determine, in the context of five-dimensional gauged
supergravity with vector and hypermultiplets, the conditions under which curved
(non Ricci flat) supersymmetric domain wall solutions may exist. These curved
BPS domain wall solutions may, in general, be supported by non-constant vector
and hyper scalar fields. We establish our results by a careful analysis of the
BPS equations as well as of the associated integrability conditions and the
equations of motion. We construct an example of a curved BPS solution in a
gauged supergravity model with one hypermultiplet. We also discuss the dual
description of curved BPS domain walls in terms of RG flows.Comment: 18 pages, LaTeX, 5 figures; added reference
Intersecting D-Branes in ten and six dimensions
We show how, via -duality, intersecting -Brane configurations in ten
(six) dimensions can be obtained from the elementary -Brane configurations
by embedding a Type IIB -Brane into a Type IIB Nine-Brane (Five-Brane) and
give a classification of such configurations. We show that only a very specific
subclass of these configurations can be realized as (supersymmetric) solutions
to the equations of motion of IIA/IIB supergravity. Whereas the elementary
-brane solutions in are characterized by a single harmonic function,
those in contain two independent harmonic functions and may be viewed as
the intersection of two elementary -branes. Using
string/string/string triality in six dimensions we show that the heterotic
version of the elementary -Brane solutions correspond in ten
dimensions to intersecting Neveu-Schwarz/Neveu-Schwarz (NS/NS) strings or
five-branes and their -duals. We comment on the implications of our results
in other than ten and six dimensions.Comment: 18 pages, Latex, (substantial changes in section 2
BPS equations in N=2, D=5 supergravity with hypermultiplets
With the general aim to classify BPS solutions in N=2, D=5 supergravities
interacting with an arbitrary number of vector, tensor and hypermultiplets,
here we begin considering the most general electrostatic, spherical-symmetric
BPS solutions in the presence of hypermultiplet couplings. We discuss the
properties of the BPS equations and the restrictions imposed by their
integrability conditions. We exhibit explicit solutions for the case of static
BPS black-holes coupled to one (the so called universal) hypermultiplet.Comment: 20 pages, v3 some corrections performed; we thank A.Van Proeyen for
the pointing ou
Supersymmetric Balance of Forces and Condensation of BPS States
Until now all known static multi black hole solutions described BPS states
with charges of the same sign. Such solutions could not be related to flat
directions in the space of BPS states. The total number of such states could
not spontaneously increase because of the charge conservation. We show that
there exist static BPS configurations which remain in equilibrium even if they
consist of states with opposite electric (or magnetic) charges from vector
multiplets. This is possible because of the exact cancellation between the
Coulomb and scalar forces. In particular, in the theories with N=4 or N=2
supersymmetry there exist stable massless multi center configurations with
vanishing total charge. Since such configurations have vanishing energy and
charge independently of their number, they can be associated with flat
directions in the space of all possible BPS states. For N=2 case this provides
a realization of the idea that BPS condensates could relate to each other
different vacua of the string theory.Comment: 19 pages, LaTe
A model realisation of the Jaffe-Wilczek correlation for pentaquarks
We discuss a realisation of the pentaquark structure proposed by Jaffe and
Wilczek within a simple quark model with colour-spin contact interactions and
coloured harmonic confinement, which accurately describes the
splitting. In this model spatially compact diquarks are formed in the
pentaquark but no such compact object exists in the nucleon. The colour-spin
attraction brings the Jaffe-Wilczek-like state down to a low mass, compatible
with the experimental observation and below that of the naive ground state with
all -waves. We find, however, that although these trends are maintained, the
extreme effects observed do not survive the required ``smearing'' of the delta
function contact interaction. We also demonstrate the weakness of the
``schematic'' approximation when applied to a system containing a -wave. An
estimate of the anti-charmed pentaquark mass is made which is in line with the
Jaffe-Wilczek prediction and significantly less than the value reported by the
H1 collaboration.Comment: 10 pages, uses psfra
Four-dimensional High-Branes as Intersecting D-Branes
We show that a class of extremal four-dimensional supersymmetric
``high-branes'', i.e. string and domain wall solutions, can be interpreted as
intersections of four ten-dimensional Dirichlet branes. These solutions
are related, via -duality in ten dimensions, to the four-dimensional
extremal Maxwell/scalar black holes that are characterized by a scalar coupling
parameter with .Comment: 9 pages, Latex, typos and minor errors correcte
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