183 research outputs found
Evidence for the classical integrability of the complete AdS(4) x CP(3) superstring
We construct a zero-curvature Lax connection in a sub-sector of the
superstring theory on AdS(4) x CP(3) which is not described by the
OSp(6|4)/U(3) x SO(1,3) supercoset sigma-model. In this sub-sector worldsheet
fermions associated to eight broken supersymmetries of the type IIA background
are physical fields. As such, the prescription for the construction of the Lax
connection based on the Z_4-automorphism of the isometry superalgebra OSp(6|4)
does not do the job. So, to construct the Lax connection we have used an
alternative method which nevertheless relies on the isometry of the target
superspace and kappa-symmetry of the Green-Schwarz superstring.Comment: 1+26 pages; v2: minor typos corrected, acknowledgements adde
Action for the eleven dimensional multiple M-wave system
We present the covariant supersymmetric and kappa-symmetric action for a
system of N nearly coincident M-waves (multiple M0-brane system) in flat eleven
dimensional superspace.Comment: 4+ pages, RevTeX4, no figures. V2: misprints corrected, discussion
extended, references added, LaTeX, 10 pages. V3: misprints corrected. V4,
extended version, 1+13 pages, to appear in JHE
Ectoplasm with an Edge
The construction of supersymmetric invariant actions on a spacetime manifold
with a boundary is carried out using the "ectoplasm" formalism for the
construction of closed forms in superspace. Non-trivial actions are obtained
from the pull-backs to the bosonic bodies of closed but non-exact forms in
superspace; finding supersymmetric invariants thus becomes a cohomology
problem. For a spacetime with a boundary, the appropriate mathematical language
changes to relative cohomology, which we use to give a general formulation of
off-shell supersymmetric invariants in the presence of boundaries. We also
relate this construction to the superembedding formalism for the construction
of brane actions, and we give examples with bulk spacetimes of dimension 3, 4
and 5. The closed superform in the 5D example needs to be constructed as a
Chern-Simons type of invariant, obtained from a closed 6-form displaying Weil
triviality.Comment: 25 page
Ten-Dimensional Super-Twistors and Super-Yang-Mills
Four-dimensional super-twistors provide a compact covariant description of
on-shell N=4 d=4 super-Yang-Mills. In this paper, ten-dimensional
super-twistors are introduced which similarly provide a compact covariant
description of on-shell d=10 super-Yang-Mills. The super-twistor variables are
Z=(lambda^alpha, mu_alpha, Gamma^m) where lambda^alpha and mu_alpha are
constrained bosonic d=10 spinors and Gamma^m is a constrained fermionic d=10
vector. The Penrose map relates the twistor superfield Phi(Z) with the d=10
super-Yang-Mills vertex operator lambda^alpha A_alpha(x,theta) which appears in
the pure spinor formalism of the superstring, and the cubic super-Yang-Mills
amplitude is proportional to the super-twistor integral \int dZ Phi_1 Phi_2
Phi_3.Comment: 14 pages harvmac, added short clarificatio
Pure Spinor Approach to Type IIA Superstring Sigma Models and Free Differential Algebras
This paper considers the Free Differential Algebra and rheonomic
parametrization of type IIA Supergravity, extended to include the BRS
differential and the ghosts. We consider not only the ghosts lambda's of
supersymmetry but also the ghosts corresponding to gauge and Lorentz
transformations. In this way we can derive not only the BRS transformations of
fields and ghosts but also the standard pure spinor constraints on lambda's.
Moreover the formalism allows to derive the action for the pure spinor
formulation of type IIA superstrings in a general background, recovering the
action first obtained by Berkovits and Howe.Comment: 1+23 pages, v2: added clarifications and a reference, misprints
corrected, v3: presentation improved, results unchange
Supersymmetric AdS vacua and separation of scales
The moduli space of the supersymmetric massive IIA AdS4xS2(B4) vacua, where
S2(B4) is a two-sphere bundle over a four-dimensional Kaehler-Einstein base B4,
includes three independent parameters which can be thought of as corresponding
to the sizes of AdS4, B4 and the S2 fiber. It might therefore be expected that
these vacua do not suffer from the absence of scale separation. We show that
the independence of the geometric moduli survives flux quantization. However,
we uncover an attractor behavior whereby all sizes flow to equality in some
neighborhood of spacetime independently of the initial conditions set by the
parameters of the solution. This is further confirmed by the study of the ratio
of internal to external scalar curvatures. We also show that the asymptotic
Kaluza-Klein spectrum of a ten-dimensional massive scalar is governed by a
scale of the order of the AdS4 radius. Furthermore we point out that the
curvature ratio in supersymmetric IIA AdS4 vacua with rigid SU(3) structure is
of order one, indicating the absence of scale separation in this large class of
vacua.Comment: 21 pages, 2 figures; v2 typos correcte
Free Differential Algebras and Pure Spinor Action in IIB Superstring Sigma Models
In this paper we extend to the case of IIB superstring sigma models the
method proposed in hep-th/10023500 to derive the pure spinor approach for type
IIA sigma models. In particular, starting from the (Free) Differential Algebra
and superspace parametrization of type IIB supergravity, extended to include
the BRST differential and all the ghosts, we derive the BRST transformations of
fields and ghosts as well as the standard pure spinor constraints for the
ghosts related to supersymmetry. Moreover, using the method first
proposed by us, we derive the pure spinor action for type IIB superstrings in
curved supergravity backgrounds (on shell), in full agreement with the action
first obtained by Berkovits and Howe.Comment: 24 page
Flux compactification on smooth, compact three-dimensional toric varieties
Three-dimensional smooth, compact toric varieties (SCTV), when viewed as real
six-dimensional manifolds, can admit G-structures rendering them suitable for
internal manifolds in supersymmetric flux compactifications. We develop
techniques which allow us to systematically construct G-structures on SCTV and
read off their torsion classes. We illustrate our methods with explicit
examples, one of which consists of an infinite class of toric CP^1 bundles. We
give a self-contained review of the relevant concepts from toric geometry, in
particular the subject of the classification of SCTV in dimensions less or
equal to 3. Our results open up the possibility for a systematic construction
and study of supersymmetric flux vacua based on SCTV.Comment: 27 pages, 10 figures; v2: references, minor typos & improvement
The gauge dual of Romans mass
We deform the recently proposed holographic duality between the ABJM N=6
Chern-Simons-matter theory and type IIA string theory in AdS4xCP3. We add a
non-zero Romans mass F_0, whose dual we identify as the sum of the Chern-Simons
levels for the two gauge groups. One can naturally identify four different
theories, with different amounts of supersymmetry and of flavor symmetry.Comment: 26 pages. v4: Corrected the sign for the probe brane potentia
Massive type IIA string theory cannot be strongly coupled
Understanding the strong coupling limit of massive type IIA string theory is
a longstanding problem. We argue that perhaps this problem does not exist;
namely, there may be no strongly coupled solutions of the massive theory. We
show explicitly that massive type IIA string theory can never be strongly
coupled in a weakly curved region of space-time. We illustrate our general
claim with two classes of massive solutions in AdS4xCP3: one, previously known,
with N = 1 supersymmetry, and a new one with N = 2 supersymmetry. Both
solutions are dual to d = 3 Chern-Simons-matter theories. In both these massive
examples, as the rank N of the gauge group is increased, the dilaton initially
increases in the same way as in the corresponding massless case; before it can
reach the M-theory regime, however, it enters a second regime, in which the
dilaton decreases even as N increases. In the N = 2 case, we find
supersymmetry-preserving gauge-invariant monopole operators whose mass is
independent of N. This predicts the existence of branes which stay light even
when the dilaton decreases. We show that, on the gravity side, these states
originate from D2-D0 bound states wrapping the vanishing two-cycle of a
conifold singularity that develops at large N.Comment: 43 pages, 5 figures. v2: added reference
- …