83 research outputs found
Supertubes in reduced holonomy manifolds
We show that the supertube configurations exist in all supersymmetric type
IIA backgrounds which are purely geometrical and which have, at least, one flat
direction. In other words, they exist in any spacetime of the form R^{1,1} x
M_8, with M_8 any of the usual reduced holonomy manifolds. These generalised
supertubes preserve 1/4 of the supersymmetries preserved by the choice of the
manifold M_8. We also support this picture with the construction of their
corresponding family of IIA supergravity backgrounds preserving from 1/4 to
1/32 of the total supercharges.Comment: 20 page
Galilean Superconformal Symmetries
We consider the non-relativistic c -> \infty contraction limit of the (N=2k)-
extended D=4 superconformal algebra su(2,2;N), introducing in this way the
non-relativistic (N=2k)-extended Galilean superconformal algebra. Such a
Galilean superconformal algebra has the same number of generators as
su(2,2|2k). The usp(2k) algebra describes the non-relativistic internal
symmetries, and the generators from the coset u(2k)/usp(2k) become central
charges after contraction.Comment: 15 pages; v3:2 reference added, misprints corrected. Version to
appear in PL
Non-Relativistic Non-BPS Dp-brane
We construct non-relativistic non-BPS Dp-brane action. Then we will study the
properties of the tachyon kink solution on its world-volume. We will argue that
this tachyon kink describes non-relativistic D(p-1)-brane.Comment: 20 page
Let's Twist Again: General Metrics of G(2) Holonomy from Gauged Supergravity
We construct all complete metrics of cohomogeneity one G(2) holonomy with S^3
x S^3 principal orbits from gauged supergravity. Our approach rests on a
generalization of the twisting procedure used in this framework. It corresponds
to a non-trivial embedding of the special Lagrangian three-cycle wrapped by the
D6-branes in the lower dimensional supergravity. There are constraints that
neatly reduce the general ansatz to a six functions one. Within this approach,
the Hitchin system and the flop transformation are nicely realized in eight
dimensional gauged supergravity.Comment: 31 pages, latex; v2: minor changes, references adde
Stem cell differentiation increases membrane-actin adhesion regulating cell blebability, migration and mechanics
This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder in order to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/K. S. is funded by an EPSRC PhD studentship. S.T. is funded by an EU Marie Curie Intra European Fellowship (GENOMICDIFF)
Wrapped branes with fluxes in 8d gauged supergravity
We study the gravity dual of several wrapped D-brane configurations in
presence of 4-form RR fluxes partially piercing the unwrapped directions. We
present a systematic approach to obtain these solutions from those without
fluxes. We use D=8 gauged supergravity as a starting point to build up these
solutions. The configurations include (smeared) M2-branes at the tip of a G_2
cone on S^3 x S^3, D2-D6 branes with the latter wrapping a special Lagrangian
3-cycle of the complex deformed conifold and an holomorphic sphere in its
cotangent bundle T^*S^2, D3-branes at the tip of the generalized resolved
conifold, and others obtained by means of T duality and KK reduction. We
elaborate on the corresponding N=1 and N=2 field theories in 2+1 dimensions.Comment: 32 pages, LateX, v2: minor changes, reference added, v3: section
3.5.2 improve
Galileons as Wess-Zumino Terms
We show that the galileons can be thought of as Wess-Zumino terms for the
spontaneous breaking of space-time symmetries. Wess-Zumino terms are terms
which are not captured by the coset construction for phenomenological
Lagrangians with broken symmetries. Rather they are, in d space-time
dimensions, d-form potentials for (d+1)-forms which are non-trivial co-cycles
in Lie algebra cohomology of the full symmetry group relative to the unbroken
symmetry group. We introduce the galileon algebras and construct the
non-trivial (d+1)-form co-cycles, showing that the presence of galileons and
multi-galileons in all dimensions is counted by the dimensions of particular
Lie algebra cohomology groups. We also discuss the DBI and conformal galileons
from this point of view, showing that they are not Wess-Zumino terms, with one
exception in each case.Comment: 49 pages. v2 minor changes, version appearing in JHE
- …