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 $R$-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 ${\cal N}=2$ 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 $T$-duality, intersecting $D$-Brane configurations in ten (six) dimensions can be obtained from the elementary $D$-Brane configurations by embedding a Type IIB $D$-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 $D$-brane solutions in $d=10$ are characterized by a single harmonic function, those in $d=6$ contain two independent harmonic functions and may be viewed as the intersection of two $d=10$ elementary $D$-branes. Using string/string/string triality in six dimensions we show that the heterotic version of the elementary $d=6$ $D$-Brane solutions correspond in ten dimensions to intersecting Neveu-Schwarz/Neveu-Schwarz (NS/NS) strings or five-branes and their $T$-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 $\Delta-N$ 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 $S$-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 $P$-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 $d=4$ solutions are related, via $T$-duality in ten dimensions, to the four-dimensional extremal Maxwell/scalar black holes that are characterized by a scalar coupling parameter $a$ with $a=0,1/\sqrt{3}, 1, \sqrt{3}$.Comment: 9 pages, Latex, typos and minor errors correcte