202 research outputs found
Wrapping rules (in) string theory
In this paper we show that the number of all 1/2-BPS branes in string theory
compactified on a torus can be derived by universal wrapping rules whose
formulation we present. These rules even apply to branes in less than ten
dimensions whose ten-dimensional origin is an exotic brane. In that case the
wrapping rules contain an additional combinatorial factor that is related to
the highest dimension in which the ten-dimensional exotic brane, after
compactification, can be realized as a standard brane. We show that the
wrapping rules also apply to cases with less supersymmetry. As a specific
example, we discuss the compactification of IIA/IIB string theory on
.Comment: 21 page
BPS Open Strings and A-D-E-singularities in F-theory on K3
We improve on a recently constructed graphical representation of the
supergravity 7-brane solution and apply this refined representation to re-study
the open string description of the A-D-E-singularities in F-theory on K3. A
noteworthy feature of the graphical representation is that it provides the
complete global branch cut structure of the 7-brane solution which plays an
important role in our analysis. We first identify those groups of branes which
when made to coincide lead to the A-D-E-gauge groups. We next show that there
is always a sufficient number of open BPS strings to account for all the
generators of the gauge group. However, as we will show, there is in general no
one-to-one relation between BPS strings and gauge group generators.
For the D_{n+4}- and E-singularities, in order to relate BPS strings with
gauge group generators, we make an SU(n+4), respectively SU(5) subgroup of the
D_{n+4}- and E-gauge groups manifest. We find that only for the D-series (and
for the standard A-series) this is sufficient to identify, in a one-to-one
manner, which BPS strings correspond to which gauge group generators.Comment: 37 pages, 15 figure
Three-Dimensional Extended Bargmann Supergravity
We show that three-dimensional General Relativity, augmented with two vector
fields, allows for a non-relativistic limit, different from the standard limit
leading to Newtonian gravity, that results into a well-defined action which is
of the Chern-Simons type. We show that this three-dimensional `Extended
Bargmann Gravity', after coupling to matter, leads to equations of motion
allowing a wider class of background geometries than the ones that one
encounters in Newtonian gravity. We give the supersymmetric generalization of
these results and point out an important application in the context of
calculating partition functions of non-relativistic field theories using
localization techniques.Comment: 6 pages, v2: typo's corrected, reference updated, accepted for
publication in Phys. Rev. Let
Defect Branes
We discuss some general properties of "defect branes", i.e. branes of
co-dimension two, in (toroidally compactified) IIA/IIB string theory. In
particular, we give a full classification of the supersymmetric defect branes
in dimensions 2 < D < 11 as well as their higher-dimensionalstring and M-theory
origin as branes and a set of "generalized" Kaluza-Klein monopoles. We point
out a relation between the generalized Kaluza-Klein monopole solutions and a
particular type of mixed-symmetry tensors. These mixed-symmetry tensors can be
defined at the linearized level as duals of the supergravity potentials that
describe propagating degrees of freedom. It is noted that the number of
supersymmetric defect branes is always twice the number of corresponding
central charges in the supersymmetry algebra.Comment: Latex2e paper, 28 pages, no figures. Footnote adde
Towards a classification of branes in theories with eight supercharges
We provide a classification of half-supersymmetric branes in quarter-maximal
supergravity theories with scalars parametrising coset manifolds. Guided by the
results previously obtained for the half-maximal theories, we are able to show
that half-supersymmetric branes correspond to the real longest weights of the
representations of the brane charges, where the reality properties of the
weights are determined from the Tits-Satake diagrams associated to the global
symmetry groups. We show that the resulting brane structure is universal for
all theories that can be uplifted to six dimensions. We also show that when
viewing these theories as low-energy theories for the suitably compactified
heterotic string, the classification we obtain is in perfect agreement with the
wrapping rules derived in previous works for the same theory compactified on
tori. Finally, we relate the branes to the R-symmetry representations of the
central charges and we show that in general the degeneracies of the BPS
conditions are twice those of the half-maximal theories and four times those of
the maximal ones.Comment: 47 pages, 8 figure
Torsional Newton-Cartan Geometry and the Schr\"odinger Algebra
We show that by gauging the Schr\"odinger algebra with critical exponent
and imposing suitable curvature constraints, that make diffeomorphisms
equivalent to time and space translations, one obtains a geometric structure
known as (twistless) torsional Newton-Cartan geometry (TTNC). This is a version
of torsional Newton-Cartan geometry (TNC) in which the timelike vielbein
must be hypersurface orthogonal. For this version of TTNC
geometry is very closely related to the one appearing in holographic duals of
Lifshitz space-times based on Einstein gravity coupled to massive vector
fields in the bulk. For there is however an extra degree of freedom
that does not appear in the holographic setup. We show that the result of
the gauging procedure can be extended to include a St\"uckelberg scalar
that shifts under the particle number generator of the Schr\"odinger algebra,
as well as an extra special conformal symmetry that allows one to gauge away
. The resulting version of TTNC geometry is the one that appears in the
holographic setup. This shows that Schr\"odinger symmetries play a crucial role
in holography for Lifshitz space-times and that in fact the entire boundary
geometry is dictated by local Schr\"odinger invariance. Finally we show how to
extend the formalism to generic torsional Newton-Cartan geometries by relaxing
the hypersurface orthogonality condition for the timelike vielbein .Comment: v2: 38 pages, references adde
Properties of Non-relativistic Neveu-Schwarz Gravity
We show how the common low-energy effective action of the different non-relativistic string theories, called non-relativistic Neveu-Schwarz gravity, can be obtained by taking a particular limit of the relativistic low-energy effective action. We discuss some distinguishing features of this non-relativistic Neveu-Schwarz gravity theory
SL(2,R)-invariant IIB Brane Actions
We give a universal SL(2,R)-invariant expression for all IIB p-brane actions
with p=-1,1,3,5,7,9. The Wess-Zumino terms in the brane actions are determined
by requiring (i) target space gauge invariance and (ii) the presence of a
single Born-Infeld vector. We find that for p=7 (p=9) brane actions with these
properties only exist for orbits that contain the standard D7-brane (D9-brane).
We comment about the actions for the other orbits.Comment: 15 pages, additional references and remarks in subsection on
3-branes, accepted for publication in JHE
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